Multi-layer golf ball with translucent cover

ABSTRACT

A golf ball comprising a core, a cover and at least on intermediate layer therebetween. The intermediate layer includes pigment which contributes to the color or appearance of the ball and the cover is at least partially transparent such that the intermediate layer is at least partially visible. The cover is also comprised of an optical enhancer.

FIELD OF THE INVENTION

[0001] The invention relates generally to golf balls and, in oneembodiment, to golf ball covers wherein the outer layer is translucent.

BACKGROUND OF THE INVENTION

[0002] Golf balls, whether of solid or wound construction, generallyinclude a core and a cover. It is known in the art to modify theproperties of a conventional solid ball by altering the typical singlelayer core and single cover layer construction to provide a ball havingat least one mantle layer disposed between the cover and the core. Thecore may be solid or liquid-filled, and may be formed of a single layeror one or more layers. Covers, in addition to cores, may also be formedof one or more layers. These multi-layer cores and covers are sometimesknown as “dual core” and “dual cover” golf balls, respectively.Additionally, many golf balls contain one or more intermediate layersthat can be of solid construction or, in many cases, be formed of atensioned elastomeric winding, which are referred to as wound balls. Thedifference in play characteristics resulting from these different typesof constructions can be quite significant. The playing characteristicsof multi-layer balls, such as spin and compression, can be tailored byvarying the properties of one or more of these intermediate and/or coverlayers.

[0003] Manufacturers generally provide the golf ball with a durablecover material, such as an ionomer resin, or a softer cover material,such as polyurethane. Chemically, ionomer resins are a copolymer of anolefin and an α,β-ethylenically-unsaturated carboxylic acid having10-90% of the carboxylic acid groups neutralized by a metal ion and aredistinguished by the type of metal ion, the amount of acid, and thedegree of neutralization. Commercially available ionomer resins includecopolymers of ethylene and methacrylic or acrylic acid neutralized withmetal salts. Examples include SURLYN® from E.I. DuPont de Nemours andCo. of Wilmington, Del. and IOTEK® from Exxon Corporation of Houston,Tex.

[0004] Surrounding the core with an ionomeric cover material provides aball that is virtually indestructible by golfers. The core/covercombination permits golfers to impart a high initial velocity to theball that results in improved distance.

[0005] Polyurethanes are used in a wide variety of applicationsincluding adhesives, sealants, coatings, fibers, injection moldingcomponents, thermoplastic parts, elastomers, and both rigid and flexiblefoams. Polyurethane can be produced by the product of a reaction betweena polyurethane prepolymer and a curing agent. The polyurethaneprepolymer is generally a product formed by a reaction between a polyoland a diisocyanate. The curing agents used previously are typicallydiamines or glycols. A catalyst is often employed to promote thereaction between the curing agent and the polyurethane prepolymer.

[0006] Since about 1960, various companies have investigated theusefulness of polyurethane as a golf ball cover material. U.S. Pat. No.4,123,061 teaches a golf ball made from a polyurethane prepolymer ofpolyether and a curing agent, such as a trifunctional polyol, atetrafunctional polyol, or a fast-reacting diamine. U.S. Pat. No.5,334,673 discloses the use of two categories of polyurethane availableon the market, i.e., thermoset and thermoplastic polyurethanes, forforming golf ball covers and, in particular, thermoset polyurethanecovered golf balls made from a composition of polyurethane prepolymerand a slow-reacting amine curing agent, and/or a difunctional glycol.

[0007] Additionally, U.S. Pat. No. 3,989,568 discloses a three-componentsystem employing either one or two polyurethane prepolymers and one ortwo polyol or fast-reacting diamine curing agents. The reactants chosenfor the system must have different rates of reactions within two or morecompeting reactions.

[0008] The color instability caused by both thermo-oxidative degradationand photodegradation typically results in a “yellowing” or “browning” ofthe polyurethane layer, an undesirable characteristic for urethanecompositions are to be used in the covers of golf balls, which aregenerally white.

[0009] U.S. Pat. No. 5,692,974 to Wu et al. discloses golf balls whichhave covers and cores and which incorporate urethane ionomers. Thepolyurethane golf ball cover has improved resiliency and initialvelocity through the addition of an alkylating agent such as t-butylchloride to induce ionic interactions in the polyurethane and therebyproduce cationic type ionomers. UV stabilizers, antioxidants, and lightstabilizers may be added to the cover composition.

[0010] U.S. Pat. No. 5,484,870 to Wu discloses a golf ball covercomprised of a polyurea. Polyureas are formed from reacting adiisocyanate with an amine.

[0011] U.S. Pat. No. 5,823,890 to Maruko et al., discloses a golf ballformed of a cover of an inner and outer cover layer compression moldedover a core. The inner and outer cover layers should have a colordifference ΔE in Lab color space of up to 3.

[0012] U.S. Pat. No. 5,840,788 to Lutz et al. discloses a UV lightresistant, visibly transparent, urethane golf ball topcoat compositionfor use with UV curable inks. The topcoat includes an optical brightenerthat absorbs at least some UV light at wavelengths greater than about350 nm, and emits visible light, and a stabilizer package. The lightstabilizer package includes at least one UV light absorber and,optionally, at least one light stabilizer, such as a HALS.

[0013] U.S. Pat. No. 5,494,291 to Kennedy discloses a golf ball having afluorescent cover and a UV light blocking, visibly transparent topcoat.The cover contains a fluorescent material that absorbs at least some UVlight at wavelengths greater than 320 nm and emits visible light.

[0014] Colored golf balls have been produced for many years. In the1960s Spalding produced a yellow range ball with a blended cover thatincluded polyurethane.

[0015] U.S. Pat. No. 4,798,386, to Berard, makes reference to whitecores and clear covers and even locating decoration on the core to bevisible through the clear cover. The Berard concept requires a corewhich has a satisfactory hue to achieve the desired finished ballcoloration. A polybutadiene rubber core of such a color has never beenproduced and as such, clear cover 2-pc ball have had limited marketsuccess.

[0016] U.S. Pat. No. 4,998,734 to Meyer, describes a golf ball with acore, a clear cover and “layer interdisposed therebetween.” However, theintermediate layer described is a thin layer of paper or plasticmaterial whose purpose is only to bear textural, alphanumeric orgraphical indicia. Meyer teaches that the layer should be sufficientlythin to permit substantial transference of impact forces from the coverto the core without substantially reducing the force.

[0017] The Pro Keds “Crystal π” golf ball appeared in the Japanesemarket. It had a white core bearing the ball markings and a clear Surlyncover. This ball had a very thick clear cover (>0.065″) and the surfacedimple coverage was very low.

[0018] In the early 1990s, Acushnet made clear Surlyn cover, two-piecePinnacle Practice balls. The covers were 0.050″ thick.

[0019] A prototype Wilson Surlyn covered two-piece ball, “Quantum”, of adesign similar to the Pro Keds ball was found in the US in the late1990s. The cover was greater than 0.065 inches thick.

[0020] U.S. Pat. No. 5,442,680, Proudfit is directed to a golf ball witha clear ionomer cover. The patent requires a blend of ionomers withdifferent cations.

[0021] In the early 1990s a solid one-piece urethane golf ball having ahole for the insertion of a chemi-luminescent tube was sold as a “NightGolf” ball. It was relatively transluscent to create the glow, but itwas far from having the performance characteristics of standard golfballs.

[0022] Two-piece balls have been sold under the tradename “Glow Owl”which utilize a white core and a cover with glow in the dark materials.This ball is believed to embody the technology described in U.S. Pat.No. 5,989,135 to Welch, which describes a “partially translucent” cover.

[0023] At the January 2001 PGA Show, Wilson displayed samples of“iWound” golf balls with clear covers. They were not balls for actualplay but mock-ups used to display their new “lattice wound” technology.The lattice (discontinuous inner cover layer) was Hytrel and the Surlynouter cover layer was clear. Both the Hytrel lattice and red core werevisible through the clear cover. No markings were on the core orlattice.

[0024] To date, it has been difficult for manufacturers to properlyattain the desired long-term appearance of polyurethane compositionsused in golf ball covers without adversely affecting golf ballperformance. Many golf balls have at least one layer of “paint” coveringthe cover material. This long-felt problem in the golf ball art has nowled the Applicants to seek a desirable formulation of a polyurethanecomposition suitable for use in golf ball covers that exhibits improvedproperties and allows for substantially different looking golf balls

SUMMARY OF THE INVENTION

[0025] The present invention is directed to a golf ball including acenter, a cover and at least one intermediate layer disposed between thecenter and the cover, wherein the cover is formed from a translucentcomposition. Preferably the cover is formed of at least one polyol oramine at least one polyisocyanate and at least one curing agent and theintermediate layer contributes the color of the ball.

[0026] A preferred embodiment of the present invention is a golf ballcomprising a center, a cover, and at least one intermediate layerdisposed between the center and the cover. The cover is formed from asubstantially translucent composition comprising polyisocyanate and theintermediate layer is comprised of pigment. Preferably, the cover issubstantially optically clear and the intermediate layer contributes tothe color of the ball. Generally, the cover has a thick ness of at least0.01 inch, has at least one of a material hardness of less than about 70Shore D, a flexural modulus of less than about 75,000 psi, and a dimplecoverage of greater than about 65% and the ball has an ATTI compressionof less than about 120.

[0027] In one embodiment, the cover includes an outer surface withindicia. In another embodiment, the intermediate layer includes an outersurface with indicia. In yet another embodiment, there is indicia onboth layers.

[0028] Preferably, the cover further comprises color stabilizercomprising a UV absorber or a light stabilizer. The UV absorbercomprises triazines, benzoxazinones, benzotriazoles, benzophenones,benzoates, formamidines, cinnamates/propenoates, aromatic propanediones,benzimidazoles, cycloaliphatic ketones, formanilides, cyanoacrylates,benzopyranones, and mixtures thereof. The UV absorber is preferablypresent in an amount between about 0.1 weight percent and about 6.0weight percent and more preferably, in an amount between about 1.0weight % to about 5.0 weight %. Most preferably, the UV absorber ispresent in an amount between about 3.0 weight % and about 5.0 weight %.

[0029] Preferably light stabilizers include bis-(substituted)heteropolycyclicdione; N,N′-1,6-hexanediylbis{N-(2,2,6,6-tetramethyl-4-piperidinyl)-formamide}; dimethyl succinatepolymer with 4-hydroxy-2,2,6,6-tetra-methyl-1-piperidine ethanol;bis-(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate; hindered amine;3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl-pyrrolidin-2,5-dione;poly-methylpropyl-3-oxy-[4(2,2,6,6-tetramethyl)piperidinyl]siloxane;bis-(1,2,2,6,6-pentamethyl-4-piperidinyl)-sebacate;bis-(2,2,6,6-tetramethyl-4-piperidinyl)-sebacate;bis-(1-octyloxy-2,2,6,6,tetramethyl-4-piperidinyl) sebacate;n-butyl-(3,5-di-t-butyl-4-hydroxybenzyl)bis-(1,2,2,6-pentamethyl-4-piperidinyl)malonate; bis-(2,2,6,6-tetramethyl-4-piperidinyl) sebacate; compoundscontaining at least one of the following structure:

[0030] and mixtures thereof. The light stabilizer is present in anamount between about 0.01 weight % and about 3 weight %. Preferably, thelight stabilizer is present in an amount between about 0.05 weight % andabout 2 weight % and most preferably, in an amount between about 0.1weight % and about 1.0 weight %.

[0031] Preferably the polyisocyanate in the cover comprises4,4′-diphenylmethane diisocyanate; polymeric 4,4′-diphenylmethanediisocyanate; carbodiimide-modified liquid 4,4′-diphenyl methanediisocyanate; 4,4′-dicyclohexylmethane diisocyanate; p-phenylenediisocyanate; toluene diisocyanate; 3,3′-dimethyl-4,4′-biphenylenediisocyanate; isophoronediisocyanate; hexamethylene diisocyanate;naphthalene diisocyanate; xylene diisocyanate; p-tetramethylxylenediisocyanate; m-tetramethylxylene diisocyanate; ethylene diisocyanate;propylene-1,2-diisocyanate; tetramethylene-1,4-diisocyanate; cyclohexyldiisocyanate; 1,6-hexamethylene-diisocyanate;dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate;cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate;1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; methylcyclohexylene diisocyanate; isocyanurate of methyl cyclohexylenediisocyanate; isocyanurate of 2,4,4-trimethyl-1,6-hexane diisocyanate;tetracene diisocyanate; napthalene diisocyanate; anthracenediisocyanate; and mixtures thereof. The cover is further comprised of acuring agent of a polyamine or a polyol. In a preferred embodiment, thetranslucent composition is comprised of a prepolymer comprising thepolyisocynate and a polyol or an amine.

[0032] In another preferred embodiment, the invention includes a golfball comprising a core, a cover and at least on intermediate layerwherein the intermediate layer is comprised of pigment which contributesto the color of the ball and the cover is at least partially transparentwith an optical enhancer. Preferably, the optical enhancer is aflorescent dye, optical brightner or an optical active chemicaladditive. Perferably, the cover is between about 0.01 and 0.05 inchesthick and is comprised of a polyisocynate. The intermediate layer ispreferably comprised of a thermoplastic elastomer of at least one color.

[0033] In a preferable embodiment, the cover is substantially opticallyclear and the intermediate layer is further comprised of an opticalbrightener. For a preferred visual effect, the cover has an outersurface that includes a plurality of dimples covering at least 80% ofthe outer surface.

[0034] In a golf ball comprised of a ball precursor and a substantiallytranslucent cover having greater than 80% of an outer surface thereofcovered by dimples, on embodiment has between about 300 and 360 dimples.Another embodiment has between about 360 and 400 dimples and yet anotherembodiment has between about 400-490 dimples.

[0035] Preferably, the translucent cover is less than about 0.05 inchthick and even between about 0.01 and 0.04 inch. The intermediate layerhas a preferable thickness of about 0.02 to 0.1 inch.

[0036] Another embodiment of the present inventor is a golf ballcomprised of a ball precursor and a substantially translucent covercomprising an optical brightener comprised of stilbene derivatives;4,4′bis-(2-benzoxazolyl)stilbene; styryl derivatives of benzene andbiphenyl; bis-(benzazol-2-yl) dirivatives; thiophene benzoxazole;coumarins; 7-(2h-naphthol (1,2-d)-triazol-2-yl)-3-phenyl-coumarin;carbostyrils; naphthalimides; derivatives ofdibenzothiophene-5,5-dioxide; pyrene derivatives; pyridotriazoles;derivatives of 4,4′-diamino stilbene-2,2′-disulfonic acid;4-methyl-7-diethylamino coumarin;2,5-bis(5-tert-butyl)-2-benzoxazolyl)thiophene; triazinolbenzenedisulfonic acid derivatives;2,2′-(1,2-ethenediylbis((3-sulfo-4,1-phenylene)imino(6-(diethylamino)-1,3,5-triazine-4,2-diyl)imino))bis-1,4-benzenedisulfonicacid hexasodium salt;2,5-thiophenediylbis(5-tert-butyl-1,3-benzooxazole; and mixturesthereof. The cover preferably has greater than 80% of an outer surfacethereof covered by dimples.

[0037] Preferably, the dimples on the golf ball according to the presentinvention are substantially round. However, other shaped dimples arecontemplated.

[0038] A preferred embodiment of the invention is a golf ball comprisedof a ball precursor and a substantially translucent cover comprisingpolyurea and having greater than 80% of an outer surface thereof coveredby dimples.

[0039] In a golf ball comprising a cover, a core and an intermediatelayer, where in the cover and the intermediate layer comprise anoptically active component effecting the appearance of the ball, thecover is preferably comprised of a florescent dye. The cover can also becomprised of an optical brightener. In another embodiment, theintermediate layer is comprised of an optical brightener. The golf ballcan also have indicia on an outer surface of the cover or on an outersurface of the intermediate layer.

[0040] In another embodiment of the present invention, the intermediatelayer is comprised of more than one color. For example, two differentcolor hemispheres can be molded to form different color halves. Inanother embodiment, two different colors can be placed in a co-injectionmachine to co-inject a multi-color intermediate layer.

BRIEF DESCRIPTION OF THE DRAWING

[0041]FIG. 1 is a cross-sectional view of a golf ball according to thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] This invention is primarily directed to golf balls having a coreof one or more layers, at least one intermediate layer, and a cover.Preferably, the golf ball cover is formed of a substantially translucentmaterial and the intermediate layer contributes to the overall color ofthe golf ball. This unique construction can provide a number ofsignificantly different looking balls that have never been made before.In one preferred embodiment, the cover is the reaction product of aprepolymer including at least one polyisocyanate and at least one polyolor polyamine with at least one curing agent. The cover may also includea color stabilizer package as set forth in detail below.

[0043] Referring to FIG. 1, the golf ball 11 of the present invention iscomprised generally of a core 12, a cover 13 and an intermediate layer14 therebetween. The core 12 is preferably solid and comprised of one ormore layers as set forth in detail below. The cover 13, discussed next,is translucent such that the intermediate layer can be seen. Theintermediate layer 14, preferably includes pigment such that it can addto the overall appearance of the ball. Preferably, the intermediatelayer 14 is a thermoplastic layer that pigment can be added to easily.

[0044] Preferably, the cover is comprised of clear, unpigmented urethaneor urea that can be cast, injection molded, compression molded orreaction injection molded over a colored golf ball precursor. Forexample, the outer cover is clear and the adjacent intermediate layer iscolored. Any color(s) may be used to create golf balls according to thepresent invention. In Japan, and to a lesser extent in the US, variouspastel shades of blue, green and others have appeared on the cover oftwo-piece balls. These colors could be obtained from using the pigmentin an inner cover layer while the outer cover includes either afluorescent dye or optically active chemical additive to further enhancethe color.

[0045] A preferred embodiment includes a clear outer layer, one as closeto optically transparent as possible, but in other embodiments a merelytranslucent layer may be preferred. The use of a lightly colored ortinted outer layer makes possible color depth characteristics notpreviously possible. Similarly, the intermediate layer and cover layerscan contain reflective or optically active particulates such asdescribed by Murphy in U.S. Pat. No. 5,427,378 which is incorporated byreference herein. In particular, these materials could be used in theintermediate layer or inner cover of the present invention and coveredwith a clear outer layer. Pearlescent pigments sold by the MearleCorporaton can also be used in this way or can be added to thesustantially clear outer layer.

[0046] If employed, it is preferable that the reflective materialcomprises at least one member selected from the group consisting ofmetal flake, iridescent glitter, metallized film and colored polyesterfoil. The reflective particles preferably have faces that have anindividual reflectance of over 75%, more preferably at least 95%, andmost preferably 99-100%. For example, flat particles with two oppositefaces can be used.

[0047] The maximum particle size of the reflective particles should besmaller than the thickness of the cover, and preferably is very small.The particle size preferably is 0.1 mm-1.0 mm more preferably 0.2 mm-0.8mm, and most preferably 0.25 mm-0.5 mm. The quantity of reflectiveparticles may vary widely, as it will depend upon the desired effect andis best determined experimentally. In general, an aesthetically pleasingreflective appearance can be obtained by using about 0.1-10, or morepreferably 1-4 parts by weight reflective particles in the material.

[0048] One of the advantages of the at least partially translucentcovers of the present invention are that smaller amounts of dye,pigment, optical brightener and/or metal flake are needed than would berequired if the covers were made of an opaque material. If an opaquecover were formed, it would be necessary to have complete color coverageon the outer surface of the cover. However, in accordance with thepresent invention pigment, dye and reflective particles which are wellbeneath the outer surface, contribute to the visibility of the ball.

[0049] Golf balls with clear covers also have a unique appearance. Theportion of the cover at edges of the dimples being thicker than thecover at the base of the dimples creates a “shadow” effect on the opaquesurface below the clear cover. The thicker the clear cover, the morepronounced the effect. For example, covers having a thickness of between0.05 and 0.1 inch. A preferred embodiment of the present invention has athinner cover with a lesser effect. In the preferred mode, the outerclear cover will have a thickness of less than about 0.050 inches. Inthe most preferred embodiment, it will be less than about 0.040 inches.The urethane and urea examples described herein have thicknesses betweenabout 0.03 and 0.035 inches.

[0050] Also, higher dimple surface coverage creates a more appealinglook. The examples described herein have dimple surface coverage inexcess of 80% of the surface of the ball. With high surface coverage anda thin cover, the edges of the dimple “shadows” merge to give theillusion that they are the surface of the ball. With sufficient dimplecoverage, the dimple shadows take on a hexagonal appearance. This ismost apparent in the optic yellow urethane and urea examples or insurlyn cover examples in which the outer cover is dyed with blue opticalbrightener.

[0051] The term optical brightener as used herein is generally the sameas that set forth in Kirk-Othmer, Encyclopedia of Chemical Technology,3d Edition, Volume 4, page 213. As there stated, optical brightenersabsorb the invisible ultra-violet portion of the daylight spectrum andconvert this energy into the longer-wavelength visible portion of thespectrum. Kirk-Othmer describes typical optical brighteners, includingstilbene derivatives, styryl derivatives of benzene and biphenyl,bis(benzazol-2-yl) derivatives, coumarins, carbostyrils, naphthalimides,derivatives of dibenzothiophene-5,5-dioxide, pyrene derivatives, andpyridotriazoles. In accordance with the present invention, any of theseor other known optical brighteners including derivatives of 4,4′-diaminostilbene-2,2′-disulfonic acid, 4-mthyl-7-diethylamino coumarin and2,5-bis(5-tert-butyl)-2-benzoxazolyl)thiophene may be used.

[0052] The amount of optically active materials to be included in thegolf ball cover layer is largely a matter of choice. The amount canrange anywhere from the minimum 0.03% level to 20% or more by weight ofthe resin solids in the clear coat. We have found an amount of about 0.3to 7% by weight to be a very desirable amount and most prefer an amountof about 0.7% to 6%. However, the brightness can be made even a littlegreater by adding a greater amount of optically active material.

[0053] Fluorescent materials useful in the present invention arecommercially available fluorescent pigments and dyes. Some are describedin U.S. Pat. Nos. 2,809,954, 2,938,873, 2,851,424 or 3,412,036 which areincorporated by reference herein. A good commercial source for theseproducts is Dayglo Color Corporation. As described in the cited patents,these fluorescent daylight materials are organic co-condensates. Theyare typically composed of melamine, an aldehyde such as formaldehyde, aheterocyclic compound and/or an aromatic sulfonamide. Typical of suchmaterials is Solvent Yellow 44, compounds which are sold by DayGlo underthe trademark Saturn Yellow and by Lawter under the trademark LemonYellow. The amount of fluorescent material to be used is largely amatter of choice depending on the brightness desired. However, it ispreferred that the amount of fluorescent dye be from about 0.01% toabout 0.5% by weight of the cover composition and the amount offluorescent pigment be from about 0.5% to about 6% by weight of thecover composition.

[0054] In general, fluorescent dyes useful in the present inventioninclude dyes from the thioxanthene, xanthene, perylene, perylene imide,coumarin, thioindigoid, naphthalimide and methine dye classes. Usefuldye classes have been more completely described in U.S. Pat. No.5,674,622, which is incorporated herein by reference in its entirety.Representative yellow fluorescent dye examples include, but are notlimited to: Lumogen F Orange.TM.240 (BASF, Rensselaer, N.Y.); Lumogen FYellow.TM.083 (BASF, Rensselaer, N.Y.); Hostasol Yellow.TM.3G(Hoechst-Celanese, Somerville, N.J.); Oraset Yellow.TM.8GF (Ciba-Geigy,Hawthorne, N.Y.); Fluorol 088.TM. (BASF, Rensselaer, N.Y.); ThermoplastF Yellow.TM.084 (BASF, Rensselaer, N.Y.); Golden Yellow.TM.D-304(DayGlo, Cleveland, Ohio); Mohawk Yellow.TM.D-299 (DayGlo, Cleveland,Ohio); Potomac Yellow.TM.D-838 (DayGlo, Cleveland, Ohio) and PolyfastBrilliant Red.TM.SB (Keystone, Chicago, Ill.)

[0055] A single fluorescent dye may be used to color an article of theinvention or a combination of one or more fluorescent dyes and/or oroptical brighteners and one or more conventional colorants may be used.

[0056] Because of the relatively unstable nature of optically activepigments and dyes, and especially because of the outside use to whichgolf balls are put, it is preferred that a U.V. stabilizer be added tothe urethane and urea cover compositions. If either the optically activematerial or the cover material comes with sufficient U.V. stabilizer, itis obviously not beneficial to add more. However, U.V. absorbers arepreferably present in the amount of from about 0.1% to about 3.0% byweight of the cover, and more preferably from about 0.5% to about 2.0%.

[0057] In another embodiment of the present invention, a conventionaldye instead of a fluorescent dye can be used. Examples of nonfluorescentdye classes that can be used in the present invention include azo,heterocyclic azo, anthraquinone, benzodifuranone, polycyclic aromaticcarbonyl, indigoid, polymethine, styryl, di- and tri-aryl carbonium,phthalocyanines, quinopphthalones, sulfur, nitro and nitroso, stilbene,and formazan dyes. The concentration of dye needed is specific to eachapplication. However, typically between about 0.01 and 1 weight percentof regular dye based on total composition cover material is perferable.It will be understood that articles with dye loadings outside this rangecan be used in accordance with this invention.

[0058] In one preferred embodiment, to maintain color of the fluorescentcover, an ultraviolet (UV) overlay layer or coating which effectivelyfilters radiation below 380 nm is use. Hindered amine light stabilizers(HALS) can also be added to ploycarbonate type matrixes to enhance thedurability of fluorescent dyes contained therein.

[0059] As discussed in more detail below, invention also relates to anembodiment comprising interpenetrating polymer networks orsemi-interpenetrating polymer networks comprising a fluorescent dye ornon-fluoresent having enhanced durability.

[0060] Interpenetrating polymer networks (IPSs), systems comprising twoindependent crosslinked polymer networks, are known to those ofordinarily skill in the art. See, for example, Encyclopedia of PolymerScience and Engineering Vol. 8, John Wiley & Sons, New York (1987) p.279 and L. H. Sperling, Introduction to Physical Polyer Science, JohnWiley & Sons (1986) pp. 46-47. In particular, IPNs comprising acrylateand urethane networks have been prepared by either sequential orsimulataneous (but independent) polymerization of free-radicallypolymerizable ethylenically-unsaturated acrylate-type monomers andurethane precursors, i.e., polyisocyanate and polyhydroxy coreactants.See, for example, U.S. Pat. Nos. 4,128,600, 4,342,793, 4,921,759,4,950,696, 4,985,340, 5,147,900, 5,256,170, 5,326,621, 5,360,462, and5,376,428 which are incorporated by reference.

[0061] Articles containing colorants are known to lose their color whenexposed to solar radiation for extended times. In particular,fluorescent colorants degrade more quickly than conventional colorants,often turning colorless on exposure to daily solar radiation in a matterof days or months. Even though they are less durable, fluorescent dyesare commonly used for increased visibility of an article due to thevisual contrast between a dyed article and its surroundings.

[0062] In another preferred embodiment, the cover comprises single phasepolymers comprising pigments or dyes such as those, for example, U.S.Pat. Nos. 3,253,146, 5,605,761, and 5,672,643 which are incorporate byreference herein.

[0063] In other embodiments comprised of fluorescent products inployvinylchloride, olefin copolymers and polyurethanes dispersal of asecond phase, preferably an acrylate phase is used. More preferably anaromatic acrylate phase, is dispersed into these thermoplastic resins.Preferably, the dispersal provides for the covalent attachment of thefluorescent dye, to assist in preventing physical loss of the dye andprovides a protective environment for the dye against photodegradation.

[0064] IPNs or semi-IPNs can include polymers that can comprise as afirst phase any of crosslinked and/or thermoplastic polyurethanes,polyureas, polyolefins, copolymers of olefins preferably with acrylates,block copolymers, polyvinyl chloride, natural and synthetic rubbers, aswell as silicone rubber, and fluoroelastomers.

[0065] The second phase of the IPNs and semi-IPNs of the invention,which is the phase that includes a dye, preferably a fluorescent dye,can be a dispersed phase or a continuous phase. Preferable polymers thatcan comprise the second phase include acrylates, epoxies, and cyanateesters. Most preferably, the second phase comprises an acrylate polymerwith aromatic content.

[0066] The advantage of this approach is that dye color retention can beimproved while maintaining desired physical properties. Depending on theproduct application, physical properties may include flexibility,strength, transparency or thermoforamability. This can be achievedthrough the used of a two-phase IPN or semi-IPN system where thefluorescent dye preferably is reacted into a crosslinked, dispersedsecond phase in a continuous first phase. Therefore, the continuousfirst phase dominates the physical properties, and the dispersed secondphase serves to anchor the dye and improve photodurability. Theadvantage lies in the independent optimization of both phases. The firstphase can be chosen for a particular physical property while thedispersed second phase can be chosen for enhanced dye photodurability.For instance, accelerated weathering studies have shown thatphotodurability is improved when the dispersed second phase comprisesaromatic components.

[0067] Golf Ball Covers Including Isocynate

[0068] Polyurethane that is useful in the present invention includes thereaction product of polyisocyanate, at least one polyol, and at leastone curing agent. Any polyisocyanate available to one of ordinary skillin the art is suitable for use according to the invention. Exemplarypolyisocyanates include, but are not limited to, 4,4′-diphenylmethanediisocyanate (“MDI”), polymeric MDI, carbodiimide-modified liquid MDI,4,4′-dicyclohexylmethane diisocyanate (“H₁₂MDI”), p-phenylenediisocyanate (“PPDI”), m-phenylene diisocyanate (“MPDI”), toluenediisocyanate (“TDI”), 3,3′-dimethyl-4,4′-biphenylene diisocyanate(“TODI”), isophoronediisocyanate (“IPDI”), hexamethylene diisocyanate(“HDI”), naphthalene diisocyanate (“NDI”); xylene diisocyanate (“XDI”);p-tetramethylxylene diisocyanate (“p-TMXDI”); m-tetramethylxylenediisocyanate (“m-TMXDI”); ethylene diisocyanate;propylene-1,2-diisocyanate; tetramethylene-1,4-diisocyanate; cyclohexyldiisocyanate; 1,6-hexamethylene-diisocyanate (“HDI”);dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate;cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate;1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; methylcyclohexylene diisocyanate; isocyanurate of HDI; triisocyanate of2,4,4-trimethyl-1,6-hexane diisocyanate (“TMDI”), tetracenediisocyanate, napthalene diisocyanate, anthracene diisocyanate, andmixtures thereof. Polyisocyanates are known to those of ordinary skillin the art as having more than one isocyanate group, e.g., di-, tri-,and tetra-isocyanate. Preferably, the polyisocyanate includes MDI, PPDI,TDI, or a mixture thereof, and more preferably, the polyisocyanateincludes MDI. It should be understood that, as used herein, the term“MDI” includes 4,4′-diphenylmethane diisocyanate, polymeric MDI,carbodiimide-modified liquid MDI, and mixtures thereof and,additionally, that the diisocyanate employed may be “low free monomer,”understood by one of ordinary skill in the art to have lower levels of“free” isocyanate monomer, typically less than about 0.1% to about 0.5%free monomer. Examples of “low free monomer” diisocyanates include, butare not limited to Low Free Monomer MDI, Low Free Monomer TDI, Low FreeMPDI, and Low Free Monomer PPDI.

[0069] The at least one polyisocyanate should have less than about 14%unreacted NCO groups. Preferably, the at least one polyisocyanate hasless than about 7.9% NCO, more preferably, between about 2.5% and about7.8%, and most preferably, between about 4% to about 6.5%.

[0070] Any polyol available to one of ordinary skill in the art issuitable for use according to the invention. Exemplary polyols include,but are not limited to, polyether polyols, hydroxy-terminatedpolybutadiene and partially/fully hydrogenated derivatives, polyesterpolyols, polycaprolactone polyols, and polycarbonate polyols. In onepreferred embodiment, the polyol includes polyether polyol, morepreferably those polyols that have the generic structure:

[0071] where R₁ and R₂ are straight or branched hydrocarbon chains, eachcontaining from 1 to about 20 carbon atoms, and n ranges from 1 to about45. Examples include, but are not limited to, polytetramethylene etherglycol, polyethylene propylene glycol, polyoxypropylene glycol, andmixtures thereof. The hydrocarbon chain can have saturated orunsaturated bonds and substituted or unsubstituted aromatic and cyclicgroups. Preferably, the polyol of the present invention includes PTMEG.

[0072] In another embodiment, polyester polyols are included in thepolyurethane material of the invention. Preferred polyester polyols havethe generic structure:

[0073] where R₁ and R₂ are straight or branched hydrocarbon chains, eachcontaining from 1 to about 20 carbon atoms, and n ranges from 1 to about25. Suitable polyester polyols include, but are not limited to,polyethylene adipate glycol, polybutylene adipate glycol, polyethylenepropylene adipate glycol, ortho-phthalate-1,6-hexanediol, and mixturesthereof. The hydrocarbon chain can have saturated or unsaturated bonds,or substituted or unsubstituted aromatic and cyclic groups. In anotherembodiment, polycaprolactone polyols are included in the materials ofthe invention.

[0074] Preferably, any polycaprolactone polyols have the genericstructure:

[0075] where R₁ is a straight chain or branched hydrocarbon chaincontaining from 1 to about 20 carbon atoms, and n is the chain lengthand ranges from 1 to about 20. Suitable polycaprolactone polyolsinclude, but are not limited to, 1,6-hexanediol-initiatedpolycaprolactone, diethylene glycol initiated polycaprolactone,trimethylol propane initiated polycaprolactone, neopentyl glycolinitiated polycaprolactone, 1,4-butanediol-initiated polycaprolactone,and mixtures thereof. The hydrocarbon chain can have saturated orunsaturated bonds, or substituted or unsubstituted aromatic and cyclicgroups.

[0076] In yet another embodiment, the polycarbonate polyols are includedin the polyurethane material of the invention. Preferably, anypolycarbonate polyols have the generic structure:

[0077] where R₁ is predominantly bisphenol A units-(p-C₆H₄)—C(CH₃)₂-(p-C₆H₄)— or derivatives thereof, and n is the chainlength and ranges from 1 to about 20. Suitable polycarbonates include,but are not limited to, polyphthalate carbonate. The hydrocarbon chaincan have saturated or unsaturated bonds, or substituted or unsubstitutedaromatic and cyclic groups. In one embodiment, the molecular weight ofthe polyol is from about 200 to about 4000. Polyamine curatives are alsosuitable for use in the polyurethane composition of the invention andhave been found to improve cut, shear, and impact resistance of theresultant balls. Preferred polyamine curatives have the general formula:

[0078] where n and m each separately have values of 0, 1, 2, or 3, andwhere Y is ortho-cyclohexyl, meta-cyclohexyl, para-cyclohexyl,ortho-phenylene, meta-phenylene, or para-phenylene, or a combinationthereof. Preferred polyamine curatives include, but are not limited to,3,5-dimethylthio-2,4-toluenediamine and isomers thereof (tradenameETHACURE 100 and/or ETHACURE 100 LC); 3,5-diethyltoluene-2,4-diamine andisomers thereof, such as 3,5-diethyltoluene-2,6-diamine;4,4′-bis-(sec-butylamino)-diphenylmethane;1,4-bis-(sec-butylamino)-benzene, 4,4′-methylene-bis-(2-chloroaniline);4,4′-methylene-bis-(3-chloro-2,6-diethylaniline); trimethyleneglycol-di-p-aminobenzoate; polytetramethyleneoxide-di-p-aminobenzoate;N,N′-dialkyldiamino diphenyl methane; para, para′-methylene dianiline(MDA), m-phenylenediamine (MPDA), 4,4′-methylene-bis-(2-chloroaniline)(MOCA), 4,4′-methylene-bis-(2,6-diethylaniline),4,4′-diamino-3,3′-diethyl-5,5′-dimethyl diphenylmethane, 2,2′,3,3′-tetrachloro diamino diphenylmethane,4,4′-methylene-bis-(3-chloro-2,6-diethylaniline), (LONZACURE M-CDEA),trimethylene glycol di-p-aminobenzoate (VERSALINK 740M), and mixturesthereof. Preferably, the curing agent of the present invention includes3,5-dimethylthio-2,4-toluenediamine and isomers thereof, such asETHACURE 300, commercially available from Albermarle Corporation ofBaton Rouge, La. Suitable polyamine curatives, which include bothprimary and secondary amines, preferably have molecular weights rangingfrom about 64 to about 2000. Preferably, n and m, each separately, havevalues of 1, 2, or 3, and preferably, 1 or 2.

[0079] At least one of a diol, triol, tetraol, hydroxy-terminated, maybe added to the aforementioned polyurethane composition. Suitablehydroxy-terminated curatives have the following general chemicalstructure:

[0080] where n and m each separately have values of 0, 1, 2, or 3, andwhere X is ortho-phenylene, meta-phenylene, para-phenylene,ortho-cyclohexyl, meta-cyclohexyl, or para-cyclohexyl, or mixturesthereof. Preferably, n and m, each separately, have values of 1, 2, or3, and more preferably, 1 or 2.

[0081] Preferred hydroxy-terminated curatives for use in the presentinvention include at least one of 1,3-bis(2-hydroxyethoxy)benzene and1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene, and1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene; 1,4-butanediol;resorcinol-di-(β-hydroxyethyl)ether; andhydroquinone-di-(β-hydroxyethyl)ether; and mixtures thereof. Preferably,the hydroxy-terminated curatives have molecular weights ranging fromabout 48 to 2000. It should be understood that molecular weight, as usedherein, is the absolute weight average molecular weight and would beunderstood as such by one of ordinary skill in the art. Both thehydroxy-terminated and amine curatives can include one or moresaturated, unsaturated, aromatic, and cyclic groups. Additionally, thehydroxy-terminated and amine curatives can include one or more halogengroups. Suitable diol, triol, and tetraol groups include ethyleneglycol, diethylene glycol, polyethylene glycol, propylene glycol,polypropylene glycol, lower molecular weight polytetramethylene etherglycol, and mixtures thereof. The polyurethane composition can be formedwith a blend or mixture of curing agents. If desired, however, thepolyurethane composition may be formed with a single curing agent.

[0082] The invention is further directed to a golf ball including atranslucent cover layer formed from a composition including at least onepolyurea formed from a polyurea prepolymer and a curing agent. In oneembodiment, the polyurea prepolymer includes at least one diisocyanateand at least one polyether amine.

[0083] In this aspect of the invention the diisocyanate is preferablysaturated, and can be selected from the group consisting of ethylenediisocyanate; propylene-1,2-diisocyanate; tetramethylene diisocyanate;tetramethylene-1,4-diisocyanate; 1,6-hexamethylene-diisocyanate;octamethylene diisocyanate; decamethylene diisocyanate;2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylenediisocyanate; dodecane-1,12-diisocyanate; dicyclohexylmethanediisocyanate; cyclobutane-1,3-diisocyanate;cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate;cyclohexane-1,4-diisocyanate; methyl-cyclohexylene diisocyanate;2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate;4,4′-dicyclohexyl diisocyanate; 2,4′-dicyclohexyl diisocyanate;1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane isocyanate;1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane;isocyanatoethylcyclohexane isocyanate; bis(isocyanatomethyl)-cyclohexanediisocyanate; 4,4′-bis(isocyanatomethyl) dicyclohexane;2,4′-bis(isocyanatomethyl) dicyclohexane; isophoronediisocyanate;triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexanediisocyanate; 4,4′-dicyclohexylmethane diisocyanate;2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate;and mixtures thereof. The saturated diisocyanate is preferably selectedfrom the group consisting of isophoronediisocyanate,4,4′-dicyclohexylmethane diisocyanate, 1,6-hexamethylene diisocyanate,or a combination thereof. In another embodiment, the diisocyanate is anaromatic aliphatic isocyanate selected from the group consisting ofmeta-tetramethylxylene diisocyanate; para-tetramethylxylenediisocyanate; trimerized isocyanurate of polyisocyanate; dimerizeduredione of polyisocyanate; modified polyisocyanate; and mixturesthereof.

[0084] The polyether amine may be selected from the group consisting ofpolytetramethylene ether diamines, polyoxypropylene diamines,poly(ethylene oxide capped oxypropylene)ether diamines,triethyleneglycoldiamines, propylene oxide-based triamines,trimethylolpropane-based triamines, glycerin-based triamines, andmixtures thereof. In one embodiment, the polyether amine has a molecularweight of about 1000 to about 3000.

[0085] The curing agent may be selected from the group consisting ofhydroxy-terminated curing agents, amine-terminated curing agents, andmixtures thereof, and preferably has a molecular weight from about 250to about 4000.

[0086] In one embodiment, the hydroxy-terminated curing agents areselected from the group consisting of ethylene glycol; diethyleneglycol; polyethylene glycol; propylene glycol; 2-methyl-1,3-propanediol;2-methyl-1,4-butanediol; dipropylene glycol; polypropylene glycol;1,2-butanediol; 1,3-butanediol; 1,4-butanediol; 2,3-butanediol;2,3-dimethyl-2,3-butanediol; trimethylolpropane; cyclohexyldimethylol;triisopropanolamine; tetra-(2-hydroxypropyl)-ethylene diamine;diethylene glycol di-(aminopropyl)ether; 1,5-pentanediol;1,6-hexanediol; 1,3-bis-(2-hydroxyethoxy)cyclohexane;1,4-cyclohexyldimethylol;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane;1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane;trimethylolpropane; polytetramethylene ether glycol, preferably having amolecular weight from about 250 to about 3900; and mixtures thereof.

[0087] The amine-terminated curing agents may be selected from the groupconsisting of ethylene diamine; hexamethylene diamine;1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene diamine;2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine;4,4′-bis-(sec-butylamino)-dicyclohexylmethane;1,4-bis-(sec-butylamino)-cyclohexane;1,2-bis-(sec-butylamino)-cyclohexane; derivatives of4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 4,4′-dicyclohexylmethanediamine; 1,4-cyclohexane-bis-(methylamine);1,3-cyclohexane-bis-(methylamine); diethylene glycoldi-(aminopropyl)ether; 2-methylpentamethylene-diamine;diaminocyclohexane; diethylene triamine; triethylene tetramine;tetraethylene pentamine; propylene diamine; 1,3-diaminopropane;dimethylamino propylamine; diethylamino propylamine;imido-bis-propylamine; monoethanolamine, diethanolamine;triethanolamine; monoisopropanolamine, diisopropanolamine;isophoronediamine; and mixtures thereof.

[0088] In one embodiment, the composition further includes a catalystthat can be selected from the group consisting of a bismuth catalyst,zinc octoate, di-butyltin dilaurate, di-butyltin diacetate, tin (II)chloride, tin (IV) chloride, di-butyltin dimethoxide,dimethyl-bis[1-oxonedecyl)oxy]stannane, di-n-octyltin bis-isooctylmercaptoacetate, triethylenediamine, triethylamine, tributylamine, oleicacid, acetic acid; delayed catalysts, and mixtures thereof. The catalystmay be present from about 0.005 percent to about 1 percent by weight ofthe composition.

[0089] Any method available to one of ordinary skill in the art may beused to combine the polyisocyanate, polyol or polyamine, and curingagent of the present invention. One commonly employed method, known inthe art as a one-shot method, involves concurrent mixing of thepolyisocyanate, polyol or polyether amine, and curing agent. This methodresults in a mixture that is inhomogenous (more random) and affords themanufacturer less control over the molecular structure of the resultantcomposition. A preferred method of mixing is known as the prepolymermethod. In this method, the polyisocyanate and the polyol or polyetheramine are mixed separately prior to addition of the curing agent. Thismethod seems to afford a more homogeneous mixture resulting in a moreconsistent polymer composition.

[0090] An optional, filler component may be chosen to adjust the densityof the blends described herein, but care should be taken to make surethe optical properties remain as desired. The selection of suchfiller(s) is dependent upon the type of golf ball desired (i.e.,one-piece, two-piece multi-component, or wound), and any filleravailable to one of ordinary skill in the art is suitable for useaccording to the invention. Examples of useful fillers include zincoxide (“ZnO”), barium sulfate, calcium oxide, calcium carbonate, andsilica, as well as any salts and oxides thereof. Additional fillers,such as foaming agents, glass and/or plastic microspheres, and variousmetals, can be added to the polyurethane or polyure compositions of thepresent invention, in amounts as needed, for their well-known purposes.

[0091] It is also preferred that the composition of the presentinvention include at least one color stabilizer. Color stabilizersinclude, but are not limited to, UV absorbers, radical scavengers, suchas hindered amine light stabilizers (“HALS”), thermal stabilizers andantioxidants, quenchers, such as nickel quenchers, hydroperoxidedecomposers, fillers, and mixtures thereof. It has been determined thatfillers, such as ZnO and TiO2, pigments, and paints, have some UVabsorbing and/or blocking qualities, and as such, can contribute to thecolor stability of the composition.

[0092] Suitable UV absorbers include, but are not limited to, triazines,benzoxazinones, benzotriazoles, benzophenones, benzoates, formamidines,cinnamates/propenoates, aromatic propanediones, benzimidazoles,cycloaliphatic ketones, formanilides (including oxamides),cyanoacrylates, benzopyranones, salicylates, and mixtures thereof.Without wishing to be bound by any particular theory, it is believedthat these compounds absorb harmful UV light and rapidly convert thelight into harmless energy, such that the compounds reduce or preventthe rapid degradation of color in many conventional golf balls.

[0093] Preferred substituted triazines include those having the formula:

[0094] wherein R₁ is H, OH; R₂ is H, alkoxy, alkylester, hydroxyalkoxy;R₃ is alkyl, H; R₄ is alkyl, H, alkylester; R₅ is alkyl, H; and R₆ isalkyl, H, alkylester.

[0095] Preferred benzoxazinones include those including the formula:

[0096] Preferred benzotriazoles include those having the formula:

[0097] wherein R₁ is OH; R₂ is alkyl, hydroxyalkyl, acryloxyalkyl,(hydroxyphenyl)alkyl, (alkylester)alkyl, (hydroxyalkylether)oxoalkyl,phenylalkyl; R₃ is H, alkyl; and X is Cl, Br, I. Preferably X is Cl.

[0098] Preferred benzophenones include those having the formula:

[0099] wherein R₁ is OH, alkoxy, alkenoic acid alkoxyester, aryloxy,hydroxyalkoxy, hydroxy(alkylether)alkoxy, (polymerizedacrylo)alkoxyester, o-alkyl acid ester; R₂ is H, SO₃H, SO₃Na; and R₃ isH, OH; R₄ is H, alkoxy, OH; and R₅ is H, SO₃Na.

[0100] Preferred benzoates include those having the formula:

[0101] wherein R₁ is hydroxyalkylether, alkylphenyl, alkyl, phenyl,hydroxyphenyl; R₂ is H, OH, alkyl, hydroxy(alkylether)amino; R₃ is H,alkyl, OH; and R₄ is H, alkyl.

[0102] Preferred formamidines include those having the formula:

[0103] wherein R₁ is alkyl, R₂ is alkyl.

[0104] Preferred cinnamates or propenoates include those having theformula:

[0105] wherein R₁ is alkyl; R₂ is alkylester, cyano; R₃ is H, phenyl;and R₄ is H, alkoxy.

[0106] Preferred aromatic propanediones include those having theformula:

[0107] wherein R₁ is alkoxy; and R₂ is alkyl.

[0108] Preferred benzimidazoles include those having the formula:

[0109] Preferred cycloaliphatic ketones include those having theformula:

[0110] wherein R₁ is alkyl.

[0111] Preferred formanilides (including oxamides) include those havingthe formula:

[0112] wherein R₁ is alkyl; R₂ is H, formanilide, alkylalkoxy, and/orcontains benzimidazole.

[0113] Preferred cyanoacrylates include those having the formula:

[0114] wherein R₁ is alkyl, arylcyanoacrylalkyl; R₂ is phenyl, H,alkylindoline; and R₃ is H, phenyl.

[0115] Preferred benzopyranones include those having the formula:

[0116] wherein R₁; R₂; R₃; and R₄ are OH.

[0117] Preferred salicylates include those having the formula:

[0118] wherein R₁ is a linear, cyclic, or branched alkyl group.

[0119] The above structures are not intended to be inclusive. One ofordinary skill in the art would be aware that “cross-over” betweengroups exists, including isomeric structures, and as such, these groupsare also suitable in the compositions of the invention.

[0120] Suitable aromatic propanedione UV absorbers include, but are notlimited to, 4-t-Butyl-4′-methoxydibenzoylmethane or avobenzone, GIVSORBUV-14; and mixtures thereof.

[0121] Suitable benzimidazole UV absorbers include, but are not limitedto, 2-Phenyl-1H-benzimidazole-5-sulfonic acid, GIVSORB UV-16; andmixtures thereof.

[0122] Suitable benzophenone UV absorbers include, but are not limitedto, 2-Hydroxy-4-n-octyloxybenzophenone, UVINUL 3008;2-Hydroxy-4-methoxybenzophenone, UVINUL 3040;2-Hydroxy-4-methoxy-5-sulfobenzophenone or Sulisobenzone, UVINUL MS 40;2-(4-Benzoyl-3-hydroxyphenoxy)-2-propenoic acid ethyl ester, CYASORB UV2098; Homopolymer of 4-(2-Acryloyloxyethoxy)-2-hydroxybenzophenone,CYASORB UV 2126; 2,2′-Dihydroxy-4-methoxybenzophenone or Dioxybenzone,CYASORB UV 24; 2-Hydroxy-4-(2-hydroxy-3-decyloxypropoxy)benzophenone and2-Hydroxy-4-(2-hydroxy-3-octyloxypropoxy)benzophenone, MARK 1535;2,4,4′-Trihydroxybenzophenone, MAXGARD 200;2-Hydroxy-4-(isooctyloxy)benzophenone, MAXGARD 800;2-Hydroxy-4-dodecyloxybenzophenone, UVINUL 410;2,2′-Dihydroxy-4,4′-dimethoxy-5,5′-disulfobenzophenone, disodium salt,UVINUL 3048; 2,4-Dihydroxybenzophenone or 4-Benzoylresorcinol, UVINUL400; 2,2′-Dihydroxy-4,4′-dimethoxybenzophenone, UVINUL D 49;2,2′,4,4′-Tetrahydroxybenzophenone, UVINUL D 50;2,2′-Dihydroxy-4-(2-hydroxyethoxy)benzophenone, UVINUL X-19;2-Hydroxy-4-benzyloxybenzophenone, Seesorb 105; and mixtures thereof.

[0123] Suitable benzopyranone UV absorbers include, but are not limitedto, 3,3′,4′,5,7-pentahydroxyflavone or quercetin; and mixtures thereof.

[0124] Suitable benzotriazole UV absorbers include, but are not limitedto, 2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole,TINUVIN 329; 2-(2′-hydroxy-5′-(2-hydroxyethyl))benzotriazole, NORBLOC6000; 2-(2′-hydroxy-5′-methacrylyloxyethylphenyl)-2H-benzotriazole,NORBLOC 7966; 1,1,1-tris(hydroxyphenyl)ethane benzotriazole, THPE BZT;5-t-butyl-3-(5-chloro-2H-benzotriazol-2-yl)-4-hydroxybenzenepropanoicacid octyl ester and3-(5-chloro-2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxybenzenepropanoicacid octyl ester, TINUVIN 109;a-[3-[3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl]-1-oxopropyl]-w-hydroxypoly(oxy-1,2-ethanediyl)anda-[3-[3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl]-1-oxopropyl]-w-[3-[3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl]-1-oxopropoxy]poly(oxy-1,2-ethanediyl),TINUVIN 1130; 2-(2-Hydroxy-3,5-di-t-butylphenyl) benzotriazole, TINUVIN320; 2-(2-hydroxy-3-t-butyl-5-methylphenyl)-5-chloro-2H-benzotriazole,TINUVIN 326;2-(3′-5′-di-t-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole, TINUVIN327; 2-(2-Hydroxy-3,5-di-t-amylphenyl)benzotriazole, TINUVIN 328;3-(2H-Benzotriazol-2-yl)-5-t-butyl-4-hydroxybenzenepropanoic acid,TINUVIN 384; 2-(2H-benzotriazol-2-yl)-4-methyl-6-dodecylphenol, TINUVIN571; 3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxy-1,6-hexanediyl esterof benzenepropanoic acid and3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxy-methyl ester ofbenzenepropanoic acid, TINUVIN 840;2-[2-hydroxy-3,5-bis-(1,1-dimethylbenzyl)phenyl]-2H-benzotriazole,TINUVIN 900;2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol,TINUVIN 928;3-(2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxybenzenepropanoic acid, C7-9branched and linear alkyl esters, TINUVIN 99;2-(2-hydroxy-5-methylphenyl)benzotriazole, TINUVIN P;2-(2′-hydroxy-3′-sec-butyl-5′-t-butylphenyl)benzotriazole, TINUVIN 350;2-(2′-hydroxy-5′-t-butylphenyl) benzotriazole, TINUVIN PS;bis[2-hydroxy-3-(2H-benzotriazol-2-yl)-5-octylphenyl]methane, TINUVIN360; and mixtures thereof.

[0125] Suitable benzoate UV absorbers include, but are not limited to,hexadecyl 3,5-di-t-butyl-4-hydroxybenzoate, CYASORB UV 2908;3-hydroxyphenylbenzoate, SEESORB 300;ethyl-4-[[(ethylphenylamino)methylene]amino]benzoate, GIVSORB UV-1;Phenyl 2-hydroxybenzoate or phenylsalicylate, SEESORB 201;2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, TINUVIN 120;4-Bis(polyethoxy)amino acid polyethoxy ethyl ester, UVINUL P 25;4-t-Butylphenyl 2-hydroxybenzoate or 4-t-butylphenylsalicylate, Seesorb202; and mixtures thereof.

[0126] Suitable benzoxazinone UV absorbers include, but are not limitedto, 2,2′-(p-phenylene)di-3,1-benzoxazin-4-one, CYASORB 3638; andmixtures thereof.

[0127] Suitable cinnamates or propenoate UV absorbers include, but arenot limited to, dimethyl(p-methoxybenzylidene)malonate, SANDUVOR PR 25;3-(4-methoxyphenyl)-2-propenoic acid 2-ethylhexyl ester or octylp-methoxycinnamate, UVINUL 3039; and mixtures thereof.

[0128] Suitable cyanoacrylate UV absorbers include, but are not limitedto, ethyl-2-cyano-3,3-diphenylacrylate, UVINUL 3035;2-ethylhexyl-2-cyano-3,3-diphenylacrylate, UVINUL 3039;1,3-bis-[(2′-cyano-3,3′-diphenylacryloyl)oxy]-2,2-bis-{[(2-cyano-3′,3′-diphenylacryloyl)oxy]methyl}propane,UVINUL 3030; 2-Cyano-3-(2-methylindolinyl) methylacrylate, UV AbsorberBayer 340; and mixtures thereof.

[0129] Suitable cycloaliphatic ketone UV absorbers include, but are notlimited to, 3-(4-methylbenzylidene)-D,L-camphor, GIVSORB UV-15; andmixtures thereof.

[0130] Suitable formamidine UV absorbers include, but are not limitedto, Ethyl-4-[[(methylphenylamino)methylene]amino]benzoate, GIVSORB UV-2;and mixtures thereof.

[0131] Suitable formanilide (including oxamide) UV absorbers include,but are not limited to,N-(2-ethoxyphenyl)-N′-(4-isododecylphenyl)oxamide, SANDUVOR 3206;N-[5-t-Butyl-2-ethoxyphenyl)-N′-(2-ethylphenyl)oxamide, TINUVIN 315;N-(2-ethoxyphenyl)-N′-(2-ethylphenyl)oxamide, TINUVIN 312;2H-benzimidazole-2-carboxylic acid (4-ethoxyphenyl)amide, UVINUL FK4105; and mixtures thereof.

[0132] Suitable triazine UV absorbers include, but are not limited to,2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-octyloxyphenol,CYASORB UV 1164; confidential triazine derivative, TINUVIN 1545;2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxyphenol, TINUVIN 1577 FF;2-[4-((2-Hydroxy-3-dodecyloxypropyl)oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,TINUVIN 400;2,4,6-Trianilino-p-(carbo-2′-ethylhexyl-1′-oxy)-1,3,5-triazine, UVINULT-150; and mixtures thereof.

[0133] Suitable salicylate UV absorbers include, but are not limited to,3,3,5-trimetylcyclohexylsalicylate or homomentyylsalicylate, NEOHELIOPAN HMS; menthyl-o-aminobenzoate, NEO HELIOPAN MA; and mixturesthereof.

[0134] The TINUVIN compounds are commercially available from CibaSpecialty Chemicals Corporation of Tarrytown, N.Y.; UVINULS arecommercially available from BASF Corporation of Charlotte, N.C.;CYASORBS are commercially available from Cytec Industries Inc. of WestPaterson, N.J.; SANDUVORS are commercially available from ClariantCorporation of Charlotte, N.C.; NORBLOCS are commercially available fromJanssen Pharmaceutica of Titusville, N.J.; Quercetin is commerciallyavailable from ACROS Organics of Pittsburgh, Pa.; MAXGARDS arecommercially available from Garrison Industries of El Dorado, Ark.;SEESORBS are commercially available from Shipro Kasei of Osaka, Japan;MARK compounds are commercially available from Witco Chemical ofOakland, N.J.; GIVSORBS are commercially available from Givauden-RoureCorp. of Geneva, Switzerland; and NEO HELIOPANS are commerciallyavailable from Haarmann & Reimer of Teterboro, N.J.

[0135] Other suitable UV absorbers include inorganic pigments such astitanium dioxide, zinc oxide, barium sulfate, violet, PALIOGEN Blue L6385, ultra marine blue, and other blue pigments; and mixtures thereof.

[0136] In a particularly preferred embodiment, the at least one UVabsorber is a liquid. Preferably, the UV absorber is a liquid when theUV absorber is present in an amount greater than about 1% of the totalpolyurethane or polyurea composition. Suitable liquid UV absorbersinclude, but are not limited to, UVINUL 3039; 2-ethylhexylp-methoxycinnamate, NEO HELIOPAN AV; UVINUL P25; isoamylp-methoxycinnamate, NEO HELIOPAN E1000; 2-ethylhexylsalicylate, NEOHELIOPAN OS; 3,3,5-trimetylcyclohexylsalicylate orhomomentyylsalicylate, NEO HELIOPAN HMS; menthyl-o-aminobenzoate, NEOHELIOPAN MA; TINUVIN 99; TINUVIN 384; TINUVIN 213; TINUVIN 1130; TINUVIN109; TINUVIN 400; TINUVIN 571; SANDUVOR 3206; MAXGARD 800; MARK 1535;GIVSORB UV-1; or mixtures thereof.

[0137] In a preferred embodiment, the selected UV absorber has anextinction coefficient, ε, of greater than about 10,000 L·mol−1·cm−1 atany wavelength between about 290 nm and about 350 nm. More preferably,the selected UV absorber has an ε of between about 10,000 L·mol−1·cm−1and about 30,000 L·mol−1·cm−·1 at wavelengths between about 290 nm andabout 350 nm, and most preferably, between about 10,000 L·mol-1·cm−1 andabout 20,000 L·mol−1·cm−1 at wavelengths between about 290 nm and about350 nm. It is believed that spectrally matching the peak absorbance ofthe UV absorber to that of the polymer composition provides the mostideal color and light stabilization. For example, UV absorbers that havean absorbance maximum at wavelengths higher than the composition havebeen found to be less effective than those that absorb at wavelengthsthat more closely match the absorbance of the polymer, even if theamplitude of the absorbance is lower. Moreover, the refractive indeciesof the UV absorber should closely match that of the polymer to maintainthe translucent properties. The indecies are preferably within 0.2 ofeach other, and more preferably within 0.05 of each other.

[0138] Preferably, the UV absorbers have certain local absorption maximabetween about 280 nm and about 400 nm, as measured in a dilute solutionof a non-hydrogen-bonding solvent, such as chloroform or methylenechloride. The UV absorbers may have a single local maximum between about300 nm to about 360 nm, more preferably between about 315 nm to about340 nm. Example include, but are not limited to, SANDUVOR VSU, UVINUL3030, SANDUVOR PR 25, GIVSORB UV-15, and mixtures thereof. Mostpreferably, the UV absorbers have two local absorption maxima, the firstbeing in the region between about 285 nm and about 315 nm, and thesecond being in the region between about 320 nm and about 370 nm.Examples of these include, but are not limited to, TINUVIN 328, NORBLOC6000, NORBLOC 7966, CYASORB 2337, TINUVIN P, GIVSORB UV-13, CYASORB3638, UVINUL D50, CYASORB UV 24, and mixtures thereof.

[0139] Without wishing to be bound by any particular theory, it isbelieved that radical scavengers, such as hindered amine lightstabilizers, function primarily as free radical scavengers. Commerciallyavailable examples include, but are not limited to,bis-(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, TINUVIN123,n-butyl-(3,5-di-t-butyl-4-hydroxybenzyl)bis-(1,2,2,6-pentamethyl-4-piperidinyl)malonate,TINUVIN 144, TINUVIN 292, TINUVIN 400, dimethyl succinate with4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, TINUVIN 622;bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate,bis-(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, TINUVIN 765; andbis-(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, TINUVIN 770 from CibaSpecialty Chemicals Corporation; dimethyl succinate with4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, CHIMASSORB 119;poly{[6-(1,1,3,3-tetramethyl(butyl)amino]-s-triazine-2,4-diyl}[(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino], CHIMASSORB 944; and1,6-hexanediamine, N,N′-bis-(2,2,6,6-tetramethyl-4-piperidinyl),CHIMASSORB 2020, also from Ciba Specialty Chemicals Corporation;CYNASORB UV-3581 from Cytec Industries Inc; SANDUVOR 3070 from ClariantCorporation of Charlotte, N.C.; UVINULS 4049H and 4050H from BASFCorporation; bis-(substituted) heteropolycyclicdione, UVINUL 4049H;N,N′-1,6-hexanediylbis{N-(2,2,6,6-tetramethyl-4-piperidinyl)-formamide}, UVINUL 4050H;dimethyl succinate polymer with4-hydroxy-2,2,6,6-tetra-methyl-1-piperidine ethanol, TINUVIN 622LD;hindered amine; SANDUVOR 3070;3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl-pyrrolidin-2,5-dione,CYASORB UV-3581;poly-methylpropyl-3-oxy-[4(2,2,6,6-tetramethyl)piperidinyl]siloxane;bis-(1,2,2,6,6-pentamethyl-4-piperidinyl)-sebacate;bis-(2,2,6,6-tetramethyl-4-piperidinyl)-sebacate;bis-(1-octyloxy-2,2,6,6,tetramethyl-4-piperidinyl) sebacate;n-butyl-(3,5-di-t-butyl-4-hydroxybenzyl)bis-(1,2,2,6-pentamethyl-4-piperidinyl)malonate; bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate; and mixturesthereof.

[0140] Examples of other suitable HALS typically include, but are notlimited to, those containing at least one of the following structure:

[0141] It is believed that thermal stabilizers and antioxidants protectpolymers against thermo-oxidative degradation. Some stabilizers include,but not limited to, IRGANOX 245, IRGANOX 1010, IRGANOX 1076, IRGANOX1135, IRGANOX 5057, and IRGANOX MD 1024 from Ciba Specialty ChemicalsCorporation; CYANOXS 790 and 1791 from Cytec Industries Inc; SANDOSTABP-EPQ from Clariant Corporation; UVINULS 2003 AO and 2012 AO from BASFCorporation; tris(mono-nonylphenyl) phosphite, UVINUL 2003 AO;1-glyceryl oleate and DL-alpha-tocopherol, UVINUL 2012 AO;triethyleneglycolbis-93-(3′-t-butyl-4′-hydroxy-5′-methyl-phenyl)-propionate, IRGANOX 245;tetrakis[3,5-di-t-butylhydroxyhydro-cinnamate)]-methane, IRGANOX 1010;3,5-di-t-4-hydroxy-hydrocinnamic acid and C₇₋₉-branched alkyl esters,IRGANOX 1135; aryl phosphonite, SANDOSTAB P-EPQ;tris(mono-nonylphenyl)phosphite, NAUGARD P; and mixtures thereof. Alsosuitable as antioxidants are many hindered phenols, such as2,6-di-t-butyl-4-methyl-phenol; 2,6-di-t-butyl-4-nonyl-phenol;2,2′-methylene-bis-(4-methyl-6-t-butyl-phenol);4,4′-butylidene-bis-(2-t-butyl-5-methyl-phenol);4,4′-thio-bis-(2-t-butyl-5-methyl-phenol);2,2′-thio-bis(6-t-butyl-4-methyl-phenol); 2,5-di-t-amyl-hydroquinone;polymeric sterically hindered phenol;octadecyl-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate;tetrakismethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane;tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate; 2,2′-thiodiethylbis-(3,5-di-t-butyl-4-hydroxyphenyl)propionate;1,1,3-tris-(2′-methyl-4′-hydroxy-5′-t-butyl-phenyl)-butane;2,2′-methylene-bis-6-(1-methyl-cyclohexyl)-papa-cresol;2,4-dimethyl-6-(1-methyl-cyclohexyl)-phenol; N,N′-hexamethylenebis-(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide);octadecyl-3,5-di-t-butyl-4-hydroxyhydrocinnamate; N-phenylbenzeneamine;reaction products with 2,4,4-trimethylpentene; and mixtures thereof.

[0142] Other suitable antioxidants include hindered phenols with thegeneric structure:

[0143] wherein R₁ and R₂ are t-butyl groups, alkyl groups, oroxyalkylenes; phosphites with the generic structure:

[0144] wherein R₁, R₂, and R₃ are alkyl groups or phenyl groups;thioesters having the generic structure:

[0145] wherein R₁, R₂, R₃, and R₄ are alkyl groups; and mixturesthereof.

[0146] Phosphites, such as tris-(2,4-di-t-butyl-phenyl)phosphite;tris-(2,4-di-t-butyl-phenyl)phosphite plusdistearyl-3,3-thiodipropionate (about 3% on phosphite);bis-(2,4-di-t-butyl-phenyl)pentaerylthritol-diphosphite;tetrakis-(2,4-di-t-butyl-phenyl) 4,4′-biphenylene-diphosphonite;tris-(p-nonylphenyl)phosphite; diisodecyl-phenyl-phosphite;diphenyl-isodecyl-phosphite; triisodecyl-phosphite; trilauryl-phosphite;and mixtures thereof, are also suitable antioxidants. Similarly, manythioesters, such as di-lauryl-3,3′-thio-dipropionate;di-stearyl-3,3′-thio-dipropionate; and mixtures thereof could be used asan antioxident.

[0147] Quenchers are light stabilizers able to take over the energyabsorbed by the chromophores present in a plastic material and todispose of it efficiently to prevent degradation. The energy can bedissipated either as heat or as fluorescent or phosphorescent radiation.For energy transfer to occur from an excited chromophore to thequencher, the latter must have lower energy states than the donor.Without wishing to be bound by any particular theory, it is believedthat the transfer can proceed according to two general mechanisms. Thefirst process, the long range energy transfer or Forester mechanism, isbased on a dipole-dipole interaction and is usually observed in thequenching of excited singlet states. The distance between chromophoreand quencher may be as large as 5 or 10 nm, provided there is a strongoverlap between the emission spectrum of the chromophore and theabsorption spectrum of the quencher. The Forester mechanism has beenconsidered as a possible stabilization mechanism by typical UV absorberswith extinction coefficients greater than 10,000 L·mol−1 cm−1. Thoughquenching of carbonyl compounds through this mechanism has beenpostulated several times it has not been shown unequivocally.

[0148] The second type of process quenchers may operate with is theso-called contact, or collisional, or exchange energy transfer. For anefficient transfer to take place, the distance between quencher andchromophore should not exceed about 1.5 nm. This means that thestabilization that can be achieved will depend on the concentration ofthe quencher and on the lifetime of the excited donor. Considering thelonger lifetimes of excited triplet states compared to those of singletstates, energy transfer from triplet states is more likely.

[0149] Suitable quenchers include, but are not limited to, nickeldibutyldithiocarbamate; thio bis2,2′-[4-(1,1,3,3-tetramethylbutyl)-phenyl]nickel-2-ethyl hexanoate;n-butylamine-nickel-2,2′-thio bis(4-t-octylphenolate);nickel-bis-[2,2′-thio bis(4-t-octylphenolate)]; and mixtures thereof,all commercially available from Ciba Corporation.

[0150] In another embodiment of the present invention, the polyurethaneor polyurea cover compositions can include in situ UV absorbers. In thisembodiment, these “reactive” UV stabilizers are chemically bounddirectly to the polymer backbone, usually to one of the prepolymercomponents. Without being bound by theory, it is believed that attachingthe stabilizers in this manner prevents migration of the stabilizers outof the polymer, and therefore increases the length of time for whichcolor stabilization is provided to the composition. Preferred in situ UVabsorbers include, but are not limited to, piperidine-based compounds.

[0151] The at least one UV stabilizer should be present in an amountbetween about 0.1 weight percent and about 6.0 weight percent, morepreferably between about 1.0 weight percent to about 5.0 weight percent,and most preferably, between about 3.0 weight percent and about 5.0weight percent. The HALS, if present, is preferably present in an amountbetween about 0.01 weight percent and about 3 weight percent, morepreferably, between about 0.05 weight percent and about 2 weightpercent, and most preferably, between about 0.1 weight percent and about1 weight percent.

[0152] In a preferred embodiment, a color stabilizer package comprisesat least one UV absorber and at least one HALS. Preferably, the ratio ofUV absorber to HALS is between about 1:1 to about 100:1, more preferablybetween about 7:1 to about 70:1, and most preferably, between about 30:1to about 60:1.

[0153] In an alternative embodiment, the polyurethane or polyureacomposition comprises at least one UV absorber and at least one HALS.Preferably, the ratio of UV absorber to HALS is between about 1:1 toabout 50:1, more preferably between about 7:1 to about 50:1, and mostpreferably, between about 30:1 to about 50:1.

[0154] Golf Ball Core Layer(s)

[0155] As used herein, the term “golf ball core” is used to refer to anyportion of a golf ball surrounded by the cover. In the case of a golfball having three or more layers, the term “golf ball core” includes atleast one inner layer and typically refers to a center surrounded by atleast one outer core layer or intermediate layer. Golf balls having atleast two layers in the core are known as “dual core” golf balls. Thecenter may be solid, gel-filled, hollow, or fluid-filled, e.g., gas orliquid. The term “inner core” is used interchangeably with “center” or“golf ball center,” while the term “outer core” is used interchangeablywith “intermediate layer” or “at least one intermediate layer.” Forexample, one optional type of intermediate layer is a tensionedelastomeric material wound about the center. An intermediate layer maybe included within a ball having, for example, a single layer ormultilayer cover, a single layer or multilayer core, both a single layercover and core, or both a multilayer cover and a multilayer core, or anysimilar such combination.

[0156] The cores of the golf balls formed according to the invention maybe solid, semi-solid, hollow, fluid-filled or powder-filled, one-pieceor multi-component cores. The term “semi-solid” as used herein refers toa paste, a gel, or the like. Any core material known to one of ordinaryskill in that art is suitable for use in the golf balls of theinvention. Suitable core materials include thermoset materials, such asrubber, styrene butadiene, polybutadiene, isoprene, polyisoprene,trans-isoprene, as well as thermoplastics such as ionomer resins,polyamides or polyesters, and thermoplastic and thermoset polyurethaneelastomers. As mentioned above, the polyurethane and polyureacompositions of the present invention may also be incorporated into anycomponent of a golf ball, including the core.

[0157] In one embodiment, the golf ball core is formed from acomposition including a base rubber (natural, synthetic, or acombination thereof), a crosslinking agent, and a filler. In anotherembodiment, the golf ball core is formed from a reaction product thatincludes a cis-to-trans catalyst, a resilient polymer component havingpolybutadiene, a free radical source, and optionally, a crosslinkingagent, a filler, or both. Various combinations of polymers, cis-to-transcatalysts, fillers, crosslinkers, and a source of free radicals, such asthose disclosed in co-pending and co-assigned U.S. patent applicationSer. No. 10/190,705, entitled “Low Compression, Resilient Golf BallsWith Rubber Core,” filed Jul. 9, 2002, the entire disclosure of which isincorporated by reference herein, may be used to form the reactionproduct. Although this polybutadiene reaction product is discussed in asection pertaining to core compositions, the present invention alsocontemplates the use of the reaction product to form at least a portionof any component of a golf ball.

[0158] To obtain a higher resilience and lower compression, ahigh-molecular weight polybutadiene with a cis-isomer content preferablygreater than about 40 percent is converted to increase the percentage oftrans-isomer content at any point in the golf ball or portion thereof.In one embodiment, the cis-isomer is present in an amount of greaterthan about 70 percent, preferably greater than about 80 percent, andmore preferably greater than about 90 percent of the total polybutadienecontent. In still another embodiment, the cis-isomer is present in anamount of greater than about 95 percent, and more preferably greaterthan about 96 percent, of the total polybutadiene content.

[0159] A low amount of 1,2-polybutadiene isomer (“vinyl-polybutadiene”)may be desired in the initial polybutadiene, and the reaction product.In one embodiment, the vinyl polybutadiene isomer content is less thanabout 7 percent, preferably less than about 4 percent, and morepreferably less than about 2 percent.

[0160] The polybutadiene material may have a molecular weight of greaterthan about 200,000. In one embodiment, the polybutadiene molecularweight is greater than about 250,000, and more preferably from about300,000 to 500,000. In another embodiment, the polybutadiene molecularweight is about 400,000 or greater. It is preferred that thepolydispersity of the material is no greater than about 2, morepreferably no greater than 1.8, and even more preferably no greater than1.6.

[0161] In one embodiment, the polybutadiene has a Mooney viscositygreater than about 20, preferably greater than about 30, and morepreferably greater than about 40. Mooney viscosity is typically measuredaccording to ASTM D-1646. In another embodiment, the Mooney viscosity ofthe polybutadiene is greater than about 35, and preferably greater thanabout 50. In one embodiment, the Mooney viscosity of the unvulcanizedpolybutadiene is from about 40 to about 80. In another embodiment, theMooney viscosity is from about 45 to about 60, more preferably fromabout 45 to about 55. It is also advantageous to mix two or morepolybutadienes having different viscosities.

[0162] In one embodiment, the center composition includes at least onerubber material having a resilience index of at least about 40. Inanother embodiment, the resilience index of the at least one rubbermaterial is at least about 50.

[0163] Examples of desirable polybutadiene rubbers include BUNA® CB22and BUNA® CB23, commercially available from Bayer of Akron, Ohio;UBEPOL® 360L and UBEPOL® 150L, commercially available from UBEIndustries of Tokyo, Japan; and CARIFLEX® BCP820 and CARIFLEX® BCP824,commercially available from Shell of Houston, Tex. If desired, thepolybutadiene can also be mixed with other elastomers known in the artsuch as natural rubber, polyisoprene rubber and/or styrene-butadienerubber in order to modify the properties of the core.

[0164] Catalyst(s)

[0165] Without being bound by any particular theory, it is believed thata cis-to-trans catalyst component, in conjunction with the free radicalsource, acts to convert a percentage of the polybutadiene polymercomponent from the cis- to the trans-conformation. Thus, thecis-to-trans conversion prefereably includes the presence of acis-to-trans catalyst, such as an organosulfur or metal-containingorganosulfur compound, a substituted or unsubstituted aromatic organiccompound that does not contain sulfur or metal, an inorganic sulfidecompound, an aromatic organometallic compound, or mixtures thereof.

[0166] As used herein, “cis-to-trans catalyst” means any component or acombination thereof that will convert at least a portion of cis-isomerto trans-isomer at a given temperature. The cis-to-trans catalystcomponent may include one or more cis-to-trans catalysts describedherein, but typically includes at least one organosulfur component, aGroup VIA component, an inorganic sulfide, or a combination thereof. Inone embodiment, the cis-to-trans catalyst is a blend of an organosulfurcomponent and an inorganic sulfide component or a Group VIA component.

[0167] As used herein when referring to the invention, the term“organosulfur compound(s)” or “organosulfur component(s),” refers to anycompound containing carbon, hydrogen, and sulfur. As used herein, theterm “sulfur component” means a component that is elemental sulfur,polymeric sulfur, or a combination thereof. It should be furtherunderstood that “elemental sulfur” refers to the ring structure of S8and that “polymeric sulfur” is a structure including at least oneadditional sulfur relative to the elemental sulfur.

[0168] The cis-to-trans catalyst is typically present in an amountsufficient to produce the reaction product so as to increase thetrans-polybutadiene isomer content to contain from about 5 percent to 70percent trans-isomer polybutadiene based on the total resilient polymercomponent. It is preferred that the cis-to-trans catalyst is present inan amount sufficient to increase the trans-polybutadiene isomer contentat least about 15 percent, more preferably at least about 20 percent,and even more preferably at least about 25 percent.

[0169] Therefore, the cis-to-trans catalyst is preferably present in anamount from about 0.1 to about 25 parts per hundred of the totalresilient polymer component. As used herein, the term “parts perhundred”, also known as “phr”, is defined as the number of parts byweight of a particular component present in a mixture, relative to 100parts by weight of the total polymer component. Mathematically, this canbe expressed as the weight of an ingredient divided by the total weightof the polymer, multiplied by a factor of 100. In one embodiment, thecis-to-trans catalyst is present in an amount from about 0.1 to about 12phr of the total resilient polymer component. In another embodiment, thecis-to-trans catalyst is present in an amount from about 0.1 to about 10phr of the total resilient polymer component. In yet another embodiment,the cis-to-trans catalyst is present in an amount from about 0.1 toabout 8 phr of the total resilient polymer component. In still anotherembodiment, the cis-to-trans catalyst is present in an amount from about0.1 to about 5 phr of the total resilient polymer component. The lowerend of the ranges stated above also may be increased if it is determinedthat 0.1 phr does not provide the desired amound of conversion. Forinstance, the amount of the cis-to-trans catalyst is present may beabout 0.5 or more, 0.75 or more, 1.0 or more, or even 1.5 or more.

[0170] Suitable organosulfur components for use in the inventioninclude, but are not limited to, at least one of diphenyl disulfide;4,4′-ditolyl disulfide; 2,2′-benzamido diphenyl disulfide;bis(2-aminophenyl)disulfide; bis(4-aminophenyl)disulfide;bis(3-aminophenyl)disulfide; 2,2′-bis(4-aminonaphthyl)disulfide;2,2′-bis(3-aminonaphthyl)disulfide; 2,2′-bis(4-aminonaphthyl)disulfide;2,2′-bis(5-aminonaphthyl)disulfide; 2,2′-bis(6-aminonaphthyl)disulfide;2,2′-bis(7-aminonaphthyl)disulfide; 2,2′-bis(8-aminonaphthyl)disulfide;1,1′-bis(2-aminonaphthyl)disulfide; 1,1′-bis(3-aminonaphthyl)disulfide;1,1′-bis(3-aminonaphthyl)disulfide; 1,1′-bis(4-aminonaphthyl)disulfide;1,1′-bis(5-aminonaphthyl)disulfide; 1,1′-bis(6-aminonaphthyl)disulfide;1,1′-bis(7-aminonaphthyl)disulfide; 1,1′-bis(8-aminonaphthyl)disulfide;1,2′-diamino-1,2′-dithiodinaphthalene;2,3′-diamino-1,2′-dithiodinaphthalene; bis(4-chlorophenyl)disulfide;bis(2-chlorophenyl)disulfide; bis(3-chlorophenyl)disulfide;bis(4-bromophenyl)disulfide; bis(2-bromophenyl)disulfide;bis(3-bromophenyl)disulfide; bis(4-fluorophenyl)disulfide;bis(4-iodophenyl)disulfide; bis(2,5-dichlorophenyl)disulfide;bis(3,5-dichlorophenyl)disulfide; bis(2,4-dichlorophenyl)disulfide;bis(2,6-dichlorophenyl)disulfide; bis(2,5-dibromophenyl)disulfide;bis(3,5-dibromophenyl)disulfide; bis(2-chloro-5-bromophenyl)disulfide;bis(2,4,6-trichlorophenyl)disulfide;bis(2,3,4,5,6-pentachlorophenyl)disulfide; bis(4-cyanophenyl)disulfide;bis(2-cyanophenyl)disulfide; bis(4-nitrophenyl)disulfide;bis(2-nitrophenyl)disulfide; 2,2′-dithiobenzoic ethyl;2,2′-dithiobenzoic methyl; 2,2′-dithiobenzoic acid; 4,4′-dithiobenzoicethyl; bis(4-acetylphenyl)disulfide; bis(2-acetylphenyl)disulfide;bis(4-formylphenyl)disulfide; bis(4carbamoylphenyl)disulfide;1,1′-dinaphthyl disulfide; 2,2′-dinaphthyl disulfide; 1,2′-dinaphthyldisulfide; 2,2′-bis(1-chlorodinaphthyl)disulfide;2,2′-bis(1-bromonaphthyl)disulfide; 1,1′-bis(2-chloronaphthyl)disulfide;2,2′-bis(1-cyanonaphtyl)disulfide; 2,2′-bis(1-acetylnaphthyl)disulfide;and the like; or a mixture thereof. Most preferred organosulfurcomponents include diphenyl disulfide, 4,4′-ditolyl disulfide, or amixture thereof, especially 4,4′-ditolyl disulfide.

[0171] In one embodiment, the at least one organosulfur component issubstantially free of metal. As used herein, the term “substantiallyfree of metal” means less than about 10 weight percent, preferably lessthan about 5 weight percent, more preferably less than about 3 weightpercent, and most preferably less than about 1 weight percent. Suitablesubstituted or unsubstituted aromatic organic components that do notinclude sulfur or a metal include, but are not limited to, diphenylacetylene, azobenzene, or a mixture thereof. The aromatic organic grouppreferably ranges in size from C₆ to C₂₀, and more preferably from C₆ toC₁₀.

[0172] In one embodiment, the organosulfur cis-to-trans catalyst ispresent in the reaction product in an amount from about 0.5 phr orgreater. In another embodiment, the cis-to-trans catalyst including aorganosulfur component is present in the reaction product in an amountfrom about 0.6 phr or greater. In yet another embodiment, thecis-to-trans catalyst including a organosulfur component is present inthe reaction product in an amount from about 1.0 phr or greater. Instill another embodiment, the cis-to-trans catalyst including aorganosulfur component is present in the reaction product in an amountfrom about 2.0 phr or greater.

[0173] Suitable metal-containing organosulfur components include, butare not limited to, cadmium, copper, lead, and tellurium analogs ofdiethyldithiocarbamate, diamyldithiocarbamate, anddimethyldithiocarbamate, or mixtures thereof. In one embodiment, themetal-containing organosulfur cis-to-trans catalyst is present in thereaction product in an amount from about 1.0 phr or greater. In anotherembodiment, the cis-to-trans catalyst including a Group VIA component ispresent in the reaction product in an amount from about 2.0 phr orgreater. In yet another embodiment, the cis-to-trans catalyst includinga Group VIA component is present in the reaction product in an amountfrom about 2.5 phr or greater. In still another embodiment, thecis-to-trans catalyst including a Group VIA component is present in thereaction product in an amount from about 3.0 phr or greater.

[0174] The organosulfur component may also be an halogenatedorganosulfur compound. Halogenated organosulfur compounds include, butare not limited to those having the following general formula:

[0175] where R₁-R₅ can be C₁-C₈ alkyl groups; halogen groups; thiolgroups (—SH), carboxylated groups; sulfonated groups; and hydrogen; inany order; and also pentafluorothiophenol; 2-fluorothiophenol;3-fluorothiophenol; 4-fluorothiophenol; 2,3-fluorothiophenol;2,4-fluorothiophenol; 3,4-fluorothiophenol; 3,5-fluorothiophenol2,3,4-fluorothiophenol; 3,4,5-fluorothiophenol;2,3,4,5-tetrafluorothiophenol; 2,3,5,6-tetrafluorothiophenol;4-chlorotetrafluorothiophenol; pentachlorothiophenol;2-chlorothiophenol; 3-chlorothiophenol; 4-chlorothiophenol;2,3-chlorothiophenol; 2,4-chlorothiophenol; 3,4-chlorothiophenol;3,5-chlorothiophenol; 2,3,4-chlorothiophenol; 3,4,5-chlorothiophenol;2,3,4,5-tetrachlorothiophenol; 2,3,5,6-tetrachlorothiophenol;pentabromothiophenol; 2-bromothiophenol; 3-bromothiophenol;4-bromothiophenol; 2,3-bromothiophenol; 2,4-bromothiophenol;3,4-bromothiophenol; 3,5-bromothiophenol; 2,3,4-bromothiophenol;3,4,5-bromothiophenol; 2,3,4,5-tetrabromothiophenol;2,3,5,6-tetrabromothiophenol; pentaiodothiophenol; 2-iodothiophenol;3-iodothiophenol; 4-iodothiophenol; 2,3-iodothiophenol;2,4-iodothiophenol; 3,4-iodothiophenol; 3,5-iodothiophenol;2,3,4-iodothiophenol; 3,4,5-iodothiophenol; 2,3,4,5-tetraiodothiophenol;2,3,5,6-tetraiodothiophenoland; and their zinc salts. Preferably, thehalogenated organosulfur compound is pentachlorothiophenol, which iscommercially available in neat form or under the tradename STRUKTOL®, aclay-based carrier containing the sulfur compound pentachlorothiophenolloaded at 45 percent (correlating to 2.4 parts PCTP). STRUKTOL® iscommercially available from Struktol Company of America of Stow, Ohio.PCTP is commercially available in neat form from eChinachem of SanFrancisco, Calif. and in the salt form from eChinachem of San Francisco,Calif. Most preferably, the halogenated organosulfur compound is thezinc salt of pentachlorothiophenol, which is commercially available fromeChinachem of San Francisco, Calif. The halogenated organosulfurcompounds of the present invention are preferably present in an amountgreater than about 2.2 phr, more preferably between about 2.3 phr andabout 5 phr, and most preferably between about 2.3 and about 4 phr.

[0176] The cis-to-trans catalyst may also include a Group VIA component.As used herein, the terms “Group VIA component” or “Group VIA element”mean a component that includes a sulfur component, selenium, tellurium,or a combination thereof. Elemental sulfur and polymeric sulfur arecommercially available from, e.g., Elastochem, Inc. of Chardon, Ohio.Exemplary sulfur catalyst compounds include PB(RM-S)-80 elemental sulfurand PB(CRST)-65 polymeric sulfur, each of which is available fromElastochem, Inc. An exemplary tellurium catalyst under the tradenameTELLOY and an exemplary selenium catalyst under the tradename VANDEX areeach commercially available from RT Vanderbilt of Norwalk, Conn.

[0177] In one embodiment, the cis-to-trans catalyst including a GroupVIA component is present in the reaction product in an amount from about0.25 phr or greater. In another embodiment, the cis-to-trans catalystincluding a Group VIA component is present in the reaction product in anamount from about 0.5 phr or greater. In yet another embodiment, thecis-to-trans catalyst including a Group VIA component is present in thereaction product in an amount from about 1.0 phr or greater.

[0178] Suitable inorganic sulfide components include, but are notlimited to titanium sulfide, manganese sulfide, and sulfide analogs ofiron, calcium, cobalt, molybdenum, tungsten, copper, selenium, yttrium,zinc, tin, and bismuth. In one embodiment, the cis-to-trans catalystincluding an inorganic sulfide component is present in the reactionproduct in an amount from about 0.5 phr or greater. In anotherembodiment, the cis-to-trans catalyst including a Group VIA component ispresent in the reaction product in an amount from about 0.75 phr orgreater. In yet another embodiment, the cis-to-trans catalyst includinga Group VIA component is present in the reaction product in an amountfrom about 1.0 phr or greater.

[0179] When a reaction product includes a blend of cis-to-transcatalysts including an organosulfur component and an inorganic sulfidecomponent, the organosulfur component is preferably present in an amountfrom about 0.5 or greater, preferably 1.0 or greater, and morepreferably about 1.5 or greater and the inorganic sulfide component ispreferably present in an amount from about 0.5 phr or greater,preferably 0.75 phr or greater, and more preferably about 1.0 phr orgreater.

[0180] A substituted or unsubstituted aromatic organic compound may alsobe included in the cis-to-trans catalyst. In one embodiment, thearomatic organic compound is substantially free of metal. Suitablesubstituted or unsubstituted aromatic organic components include, butare not limited to, components having the formula(R₁)_(x)—R₃-M-R₄—(R₂)_(y), wherein R₁ and R₂ are each hydrogen or asubstituted or unsubstituted C₁₋₂₀ linear, branched, or cyclic alkyl,alkoxy, or alkylthio group, or a single, multiple, or fused ring C₆ toC₂₄ aromatic group; x and y are each an integer from 0 to 5; R₃ and R₄are each selected from a single, multiple, or fused ring C₆ to C₂₄aromatic group; and M includes an azo group or a metal component. R₃ andR₄ are each preferably selected from a C₆ to C₁₀ aromatic group, morepreferably selected from phenyl, benzyl, naphthyl, benzamido, andbenzothiazyl. R₁ and R₂ are each preferably selected from a substitutedor unsubstituted C₁₋₁₀ linear, branched, or cyclic alkyl, alkoxy, oralkylthio group or a C₆ to C₁₀ aromatic group. When R₁, R₂, R₃, or R₄,are substituted, the substitution may include one or more of thefollowing substituent groups: hydroxy and metal salts thereof; mercaptoand metal salts thereof; halogen; amino, nitro, cyano, and amido;carboxyl including esters, acids, and metal salts thereof; silyl;acrylates and metal salts thereof; sulfonyl or sulfonamide; andphosphates and phosphites. When M is a metal component, it may be anysuitable elemental metal available to those of ordinary skill in theart. Typically, the metal will be a transition metal, althoughpreferably it is tellurium or selenium.

[0181] Free Radical Source(s)

[0182] A free-radical source, often alternatively referred to as afree-radical initiator, is preferred in the composition and method. Thefree-radical source is typically a peroxide, and preferably an organicperoxide, which decomposes during the cure cycle. Suitable free-radicalsources include organic peroxide compounds, such as di-t-amyl peroxide,di(2-t-butyl-peroxyisopropyl)benzene peroxide or α,α-bis(t-butylperoxy)diisopropylbenzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane or1,1-di(t-butylperoxy)3,3,5-trimethyl cyclohexane, dicumyl peroxide,di-t-butyl peroxide, 2,5-di-(t-butylperoxy)-2,5-dimethyl hexane,n-butyl-4,4-bis(t-butylperoxy)valerate, lauryl peroxide, benzoylperoxide, t-butyl hydroperoxide, and the like, and any mixture thereof.

[0183] Other examples include, but are not limited to, VAROX® 231XL andVarox® DCP—R, commercially available from Elf Atochem of Philadelphia,Pa.; PERKODOX® BC and PERKODOX® 14, commercially available from AkzoNobel of Chicago, Ill.; and ELASTOCHEM® DCP-70, commercially availablefrom Rhein Chemie of Trenton, N.J.

[0184] It is well known that peroxides are available in a variety offorms having different activity. The activity is typically defined bythe “active oxygen content.” For example, PERKODOX® BC peroxide is 98percent active and has an active oxygen content of 5.8 percent, whereasPERKODOX® DCP-70 is 70 percent active and has an active oxygen contentof 4.18 percent. The peroxide is may be present in an amount greaterthan about 0.1 parts per hundred of the total resilient polymercomponent, preferably about 0.1 to 15 parts per hundred of the resilientpolymer component, and more preferably about 0.2 to 5 parts per hundredof the total resilient polymer component. If the peroxide is present inpure form, it is preferably present in an amount of at least about 0.25phr, more preferably between about 0.35 phr and about 2.5 phr, and mostpreferably between about 0.5 phr and about 2 phr. Peroxides are alsoavailable in concentrate form, which are well-known to have differingactivities, as described above. In this case, if concentrate peroxidesare employed in the present invention, one skilled in the art would knowthat the concentrations suitable for pure peroxides are easily adjustedfor concentrate peroxides by dividing by the activity. For example, 2phr of a pure peroxide is equivalent 4 phr of a concentrate peroxidethat is 50 percent active (i.e., 2 divided by 0.5=4).

[0185] In one embodiment, the amount of free radical source is about 5phr or less, but also may be about 3 phr or less. In another embodiment,the amount of free radical source is about 2.5 phr or less. In yetanother embodiment, the amount of free radical source is about 2 phr orless. In still another embodiment, the amount of free radical source isabout 1 phr or less preferably about 0.75 phr or less.

[0186] It should be understood by those of ordinary skill in the artthat the presence of certain cis-to-trans catalysts according to theinvention be more suited for a larger amount of free-radical source,such as the amounts described herein, compared to conventionalcross-linking reactions. The free radical source may alternatively oradditionally be one or more of an electron beam, UV or gamma radiation,x-rays, or any other high energy radiation source capable of generatingfree radicals. It should be further understood that heat oftenfacilitates initiation of the generation of free radicals.

[0187] In one embodiment, the ratio of the free radical source to thecis-to-trans catalyst is about 10 or less, but also may be about 5 orless. Additionally, the ratio of the free radical source to thecis-to-trans catalyst may be from about 4 or less, but also may be about2 or less, and also may be about 1 or less. In another embodiment, theratio of the free radical source to the cis-to-trans catalyst is about0.5 or less, preferably about 0.4 or less. In yet another embodiment,the free radical source cis-to-trans catalyst ratio is greater thanabout 1.0. In still another embodiment, the free radical sourcecis-to-trans catalyst is about 1.5 or greater, preferably about 1.75 orgreater.

[0188] Crosslinking Agent(s)

[0189] Crosslinkers may be included to increase the hardness of thereaction product. Suitable crosslinking agents include one or moremetallic salts of unsaturated fatty acids having 3 to 8 carbon atoms,such as acrylic or methacrylic acid, or monocarboxylic acids, such aszinc, calcium, or magnesium acrylate salts, and the like, and mixturesthereof. Examples include, but are not limited to, one or more metalsalt diacrylates, dimethacrylates, and monomethacrylates, wherein themetal is magnesium, calcium, zinc, aluminum, sodium, lithium, or nickel.Preferred acrylates include zinc acrylate, zinc diacrylate, zincmethacrylate, zinc dimethacrylate, and mixtures thereof. In oneembodiment, zinc methacrylate is used in combination with the zinc saltof pentachlorothiophenol.

[0190] The crosslinking agent must be present in an amount sufficient tocrosslink a portion of the chains of polymers in the resilient polymercomponent. For example, the desired compression may be obtained byadjusting the amount of crosslinking. This may be achieved, for example,by altering the type and amount of crosslinking agent, a methodwell-known to those of ordinary skill in the art. The crosslinking agentis typically present in an amount greater than about 0.1 percent of thepolymer component, preferably from about 10 to 50 percent of the polymercomponent, more preferably from about 10 to 40 percent of the polymercomponent.

[0191] In one embodiment, the crosslinking agent is present in an amountgreater than about 10 parts per hundred (“phr”) parts of the basepolymer, preferably from about 20 to about 40 phr of the base polymer,more preferably from about 25 to about 35 phr of the base polymer.

[0192] When an organosulfur is selected as the cis-to-trans catalyst,zinc diacrylate may be selected as the crosslinking agent and is presentin an amount of less than about 25 phr.

[0193] Accelerator(s)

[0194] It is to be understood that when elemental sulfur or polymericsulfur is included in the cis-to-trans catalyst, an accelerator may beused to improve the performance of the cis-to-trans catalyst. Suitableaccelerators include, but are not limited to, sulfenamide, such asN-oxydiethylene 2-benzothiazole-sulfenamide, thiazole, such asbenzothiazyl disulfide, dithiocarbamate, such as bismuthdimethyldithiocarbamate, thiuram, such as tetrabenzyl thiuram disulfide,xanthate, such as zinc isopropyl xanthate, thiadiazine, thiourea, suchas trimethylthiourea, guanadine, such as N,N′-di-ortho-tolylguanadine,or aldehyde-amine, such as a butyraldehyde-aniline condensation product,or mixtures thereof.

[0195] Antioxidant

[0196] Typically, antioxidants are included in conventional golf ballcore compositions because antioxidants are included in the materialssupplied by manufacturers of compounds used in golf ball cores. Withoutbeing bound to any particular theory, higher amounts of antioxidant inthe reaction product may result in less trans-isomer content because theantioxidants consume at least a portion of the free radical source.Thus, even with high amounts of the free radical source in the reactionproduct described previously, such as for example about 3 phr, an amountof antioxidant greater than about 0.3 phr may significantly reduce theeffective amount of free radicals that are actually available to assistin a cis-to-trans conversion.

[0197] Because it is believed that the presence of antioxidants in thecomposition may inhibit the ability of free radicals to adequatelyassist in the cis-to-trans conversion, one way to ensure sufficientamounts of free radicals are provided for the conversion is to increasethe initial levels of free radicals present in the composition so thatsufficient amounts of free radicals remain after interaction withantioxidants in the composition. Thus, the initial amount of freeradicals provided in the composition may be increased by at least about10 percent, and more preferably are increased by at least about 25percent so that the effective amount of remaining free radicalssufficient to adequately provide the desired cis-to-trans conversion.Depending on the amount of antioxidant present in the composition, theinitial amount of free radicals may be increased by at least 50 percent,100 percent, or an even greater amount as needed. As discussed below,selection of the amount of free radicals in the composition may bedetermined based on a desired ratio of free radicals to antioxidant.

[0198] Another approach is to reduce the levels of or eliminateantioxidants in the composition. For instance, the reaction product ofthe present invention may be substantially free of antioxidants, therebyachieving greater utilization of the free radicals toward thecis-to-trans conversion. As used herein, the term “substantially free”generally means that the polybutadiene reaction product includes lessthan about 0.3 phr of antioxidant, preferably less than about 0.1 phr ofantioxidant, more preferably less than about 0.05 phr of antioxidant,and most preferably about 0.01 phr or less antioxidant.

[0199] The amount of antioxidant has been shown herein to have arelationship with the amount of trans-isomer content after conversion.For example, a polybutadiene reaction product with 0.5 phr ofantioxidant cured at 335° F. for 11 minutes results in about 15 percenttrans-isomer content at an exterior surface of the center and about 13.4percent at an interior location after the conversion reaction. Incontrast, the same polybutadiene reaction product substantially free ofantioxidants results in about 32 percent trans-isomer content at anexterior surface and about 21.4 percent at an interior location afterthe conversion reaction.

[0200] In one embodiment, the ratio of the free radical source toantioxidant is greater than about 10. In another embodiment, the ratioof the free radical source to antioxidant is greater than about 25,preferably greater than about 50. In yet another embodiment, the freeradical source-antioxidant ratio is about 100 or greater. In stillanother embodiment, the free radical source-antioxidant ratio is about200 or greater, preferably 250 or greater, and more preferably about 300or greater.

[0201] If the reaction product is substantially free of antioxidants,the amount of the free radical source is preferably about 3 phr or less.In one embodiment, the free radical source is present in an amount ofabout 2.5 phr or less, preferably about 2 phr or less. In yet anotherembodiment, the amount of the free radical source in the reactionproduct is about 1.5 phr or less, preferably about 1 phr or less. Instill another embodiment, the free radical source is present is anamount of about 0.75 phr or less.

[0202] When the reaction product contains about 0.1 phr or greaterantioxidant, the free radical source is preferably present in an amountof about 1 phr or greater. In one embodiment, when the reaction producthas about 0.1 phr or greater antioxidant, the free radical source ispresent in an amount of about 2 phr or greater. In another embodiment,the free radical source is present in an amount of about 2.5 phr orgreater when the antioxidant is present in an amount of about 0.1 phr orgreater.

[0203] In one embodiment, when the reaction product contains greaterthan about 0.05 phr of antioxidant, the free radical source ispreferably present in an amount of about 0.5 phr or greater. In anotherembodiment, when the reaction product has greater than about 0.05 phr ofantioxidant, the free radical source is present in an amount of about 2phr or greater. In yet another embodiment, the free radical source ispresent in an amount of about 2.5 phr or greater when the antioxidant ispresent in an amount of about 0.05 phr or greater.

[0204] Trans-Isomer Conversion

[0205] As discussed above, it is preferable to increase cis-isomer totrans-isomer in polybutadiene core materials. In one embodiment, theamount of trans-isomer content after conversion is at least about 10percent or greater, while in another it is about 12 percent or greater.In another embodiment, the amount of trans-isomer content is about 15percent or greater after conversion. In yet another embodiment, theamount of trans-isomer content after conversion is about 20 percent orgreater, and more preferably is about 25 percent or greater. In stillanother embodiment, the amount of trans-isomer content after conversionis about 30 percent or greater, and preferably is about 32 percent orgreater. The amount of trans-isomer after conversion also may be about35 percent or greater, about 38 percent or greater, or even about 40percent or greater. In yet another embodiment, the amount oftrans-isomer after conversion may be about 42 percent or greater, oreven about 45 percent or greater.

[0206] The cured portion of the component including the reaction productof the invention may have a first amount of trans-isomer polybutadieneat an interior location and a second amount of trans-isomerpolybutadiene at an exterior surface location. In one embodiment, theamount of trans-isomer at the exterior surface location is greater thanthe amount of trans-isomer at an interior location. As will be furtherillustrated by the examples provided herein, the difference intrans-isomer content between the exterior surface and the interiorlocation after conversion may differ depending on the cure cycle and theratios of materials used for the conversion reaction. For example, it isalso possible that these differences can reflect a center with greateramounts of trans-isomer at the interior portion than at the exteriorportion.

[0207] The exterior portion of the center may have amounts oftrans-isomer after conversion in the amounts already indicatedpreviously herein, such as in amounts about 10 percent or greater, about12 percent or greater, about 15 percent or greater, and the like, up toand including amounts that are about 45 percent or greater as statedabove. For example, in one embodiment of the invention, thepolybutadiene reaction product may contain between about 35 percent to60 percent of the trans-isomer at the exterior surface of a centerportion. Another embodiment has from about 40 percent to 50 percent oftrans-isomer at the exterior surface of a center portion. In oneembodiment, the reaction product contains about 45 percent trans-isomerpolybutadiene at the exterior surface of a center portion. In oneembodiment, the reaction product at the center of the solid centerportion may then contain at least about 20 percent less trans-isomerthan is present at the exterior surface, preferably at least about 30percent less trans-isomer, or at least about 40 percent lesstrans-isomer. In another embodiment, the amount of trans-isomer at theinterior location is at least about 6 percent less than is present atthe exterior surface, preferably at least about 10 percent less than thesecond amount.

[0208] The gradient between the interior portion of the center and theexterior portion of the center may vary. In one embodiment, thedifference in trans-isomer content between the exterior and the interiorafter conversion is about 3 percent or greater, while in anotherembodiment the difference may be about 5 percent or greater. In anotherembodiment, the difference between the exterior surface and the interiorlocation after conversion is about 10 percent or greater, and morepreferably is about 20 percent or greater. In yet another embodiment,the difference in trans-isomer content between the exterior surface andthe interior location after conversion may be about 5 percent or less,about 4 percent or less, and even about 3 percent or less. In yetanother embodiment, the difference between the exterior surface and theinterior location after conversion is less than about 1 percent.

[0209] Core Hardness

[0210] The component including the reaction product of the invention mayhave a hardness gradient, i.e., the component has a first hardness at afirst point, i.e., at an interior location, and a second hardness at asecond point, i.e., at an exterior surface, as measured on a moldedsphere. In one embodiment, the second hardness is at least about 6percent greater than the first hardness, preferably about 10 percentgreater than the first hardness. In other embodiments, the secondhardness is at least about 20 percent greater or at least about 30percent greater, than the first hardness.

[0211] For example, a reaction product of this invention shaped into aportion of a golf ball may have a first hardness of about 45 Shore C toabout 60 Shore C and a second hardness of about 65 Shore C to about 75Shore C. In one golf ball formulated according to the invention, thefirst hardness was about 51 Shore C and a second hardness was about 71Shore C, providing a hardness difference of greater than 20 percent.

[0212] The component including the reaction product may have no hardnessgradient, i.e., substantially uniform hardness throughout the component.Thus, in this aspect, the first and second hardness differ by about 5percent or less, preferably about 3 percent or less, and more preferablyby about 2 percent or less. In one embodiment, the hardness is uniformthroughout the component.

[0213] The golf ball polybutadiene material in the center typically hasa hardness of at least about 15 Shore A, preferably between about 30Shore A and 80 Shore D, more preferably between about 50 Shore A and 60Shore D. The specific gravity is typically greater than about 0.7,preferably greater than about 1, for the golf ball polybutadienematerial.

[0214] Core Compression

[0215] The compression of the core, of golf balls prepared according tothe invention is preferably between 20 and 120. As used herein, theterms “Atti compression” or “compression” are defined as the deflectionof an object or material relative to the deflection of a calibratedspring, as measured with an Atti Compression Gauge, that is commerciallyavailable from Atti Engineering Corp. of Union City, N.J. Atticompression is typically used to measure the compression of a golf ball.

[0216] In one embodiment, the core of the present invention has an Atticompression of less than about 80, more preferably, between about 40 andabout 80, and most preferably, between about 50 and about 70. In analternative, low compression embodiment, the core has a compression ofless than about 40. In one embodiment, an inner core has a compressionof less than about 20. As known to those of ordinary skill in the art,however, the cores generated according to the present invention may bebelow the measurement of the Atti Compression Gauge.

[0217] In an embodiment where the core is hard, the compression may beabout 90 or greater. In one embodiment, the compression of the hard coreranges from about 90 to about 120.

[0218] Other Properties

[0219] The polybutadiene reaction product preferably has a flexuralmodulus of from about 500 psi to 300,000 psi, preferably from about2,000 to 200,000 psi.

[0220] The desired loss tangent in the polybutadiene reaction productshould be less than about 0.15 at −60° C. and less than about 0.05 at30° C. when measured at a frequency of 1 Hz and a 1 percent strain. Inone embodiment, the polybutadiene reaction product material preferablyhas a loss tangent below about 0.1 at −50° C., and more preferably belowabout 0.07 at −50° C.

[0221] To produce golf balls having a desirable compressive stiffness,the dynamic stiffness of the polybutadiene reaction product materialshould be less than about 50,000 N/m at −50° C. Preferably, the dynamicstiffness should be between about 10,000 and 40,000 N/m at −50° C., morepreferably, the dynamic stiffness should be between about 20,000 and30,000 N/m at −50° C.

[0222] In one embodiment, the reaction product has a first dynamicstiffness measured at −50° C. that is less than about 130 percent of asecond dynamic stiffness measured at 0° C. In another embodiment, thefirst dynamic stiffness is less than about 125 percent of the seconddynamic stiffness. In yet another embodiment, the first dynamicstiffness is less than about 110 percent of the second dynamicstiffness.

[0223] Golf Ball Intermediate Layer(s)

[0224] When the golf ball of the present invention includes anintermediate layer, such as an inner cover layer or outer core layer,i.e., any layer(s) disposed between the inner core and the outer coverof a golf ball. This layer can include any materials known to those ofordinary skill in the art including thermoplastic and thermosettingmaterials. For example, the intermediate layer may be formed from any ofthe polyurea, polyurethane, and polybutadiene materials discussed above.However, certain thermoplastic materials are preferable.

[0225] The intermediate layer may also likewise include one or morehomopolymeric or copolymeric materials, such as:

[0226] (1) Vinyl resins, such as those formed by the polymerization ofvinyl chloride, or by the copolymerization of vinyl chloride with vinylacetate, acrylic esters or vinylidene chloride;

[0227] (2) Polyolefins, such as polyethylene, polypropylene,polybutylene and copolymers such as ethylene methylacrylate, ethyleneethylacrylate, ethylene vinyl acetate, ethylene methacrylic or ethyleneacrylic acid or propylene acrylic acid and copolymers and homopolymersproduced using a single-site catalyst or a metallocene catalyst;

[0228] (3) Polyurethanes, such as those prepared from polyols anddiisocyanates or polyisocyanates and those disclosed in U.S. Pat. No.5,334,673;

[0229] (4) Polyureas, such as those disclosed in U.S. Pat. No.5,484,870;

[0230] (5) Polyamides, such as poly(hexamethylene adipamide) and othersprepared from diamines and dibasic acids, as well as those from aminoacids such as poly(caprolactam), and blends of polyamides with SURLYN,polyethylene, ethylene copolymers, ethyl-propylene-non-conjugated dieneterpolymer, and the like;

[0231] (6) Acrylic resins and blends of these resins with poly vinylchloride, elastomers, and the like;

[0232] (7) Thermoplastics, such as urethanes; olefinic thermoplasticrubbers, such as blends of polyolefins withethylene-propylene-non-conjugated diene terpolymer; block copolymers ofstyrene and butadiene, isoprene or ethylene-butylene rubber; orcopoly(ether-amide), such as PEBAX, sold by ELF Atochem of Philadelphia,Pa.;

[0233] (8) Polyphenylene oxide resins or blends of polyphenylene oxidewith high impact polystyrene as sold under the trademark NORYL byGeneral Electric Company of Pittsfield, Mass.;

[0234] (9) Thermoplastic polyesters, such as polyethylene terephthalate,polybutylene terephthalate, polyethylene terephthalate/glycol modifiedand elastomers sold under the trademarks HYTREL by E.I. DuPont deNemours & Co. of Wilmington, Del., and LOMOD by General Electric Companyof Pittsfield, Mass.;

[0235] (10) Blends and alloys, including polycarbonate withacrylonitrile butadiene styrene, polybutylene terephthalate,polyethylene terephthalate, styrene maleic anhydride, polyethylene,elastomers, and the like, and polyvinyl chloride with acrylonitrilebutadiene styrene or ethylene vinyl acetate or other elastomers; and

[0236] (11) Blends of thermoplastic rubbers with polyethylene,propylene, polyacetal, nylon, polyesters, cellulose esters, and thelike.

[0237] In one embodiment, the intermediate layer includes polymers, suchas ethylene, propylene, butene-1 or hexane-1 based homopolymers orcopolymers including functional monomers, such as acrylic andmethacrylic acid and fully or partially neutralized ionomer resins andtheir blends, methyl acrylate, methyl methacrylate homopolymers andcopolymers, imidized, amino group containing polymers, polycarbonate,reinforced polyamides, polyphenylene oxide, high impact polystyrene,polyether ketone, polysulfone, poly(phenylene sulfide),acrylonitrile-butadiene, acrylic-styrene-acrylonitrile, poly(ethyleneterephthalate), poly(butylene terephthalate), poly(ethelyne vinylalcohol), poly(tetrafluoroethylene) and their copolymers includingfunctional comonomers, and blends thereof.

[0238] Ionomers

[0239] As briefly mentioned above, the intermediate layer may includeionomeric materials, such as ionic copolymers of ethylene and anunsaturated monocarboxylic acid, which are available under the trademarkSURLYN® of E.I. DuPont de Nemours & Co., of Wilmington, Del., or IOTEK®or ESCOR® of Exxon. These are copolymers or terpolymers of ethylene andmethacrylic acid or acrylic acid totally or partially neutralized, i.e.,from about 1 to about 100 percent, with salts of zinc, sodium, lithium,magnesium, potassium, calcium, manganese, nickel or the like. In oneembodiment, the carboxylic acid groups are neutralized from about 10percent to about 100 percent. The carboxylic acid groups may alsoinclude methacrylic, crotonic, maleic, fumaric or itaconic acid. Thesalts are the reaction product of an olefin having from 2 to 10 carbonatoms and an unsaturated monocarboxylic acid having 3 to 8 carbon atoms.

[0240] The intermediate layer may also include at least one ionomer,such as acid-containing ethylene copolymer ionomers, including E/X/Yterpolymers where E is ethylene, X is an acrylate or methacrylate-basedsoftening comonomer present in about 0 to 50 weight percent and Y isacrylic or methacrylic acid present in about 5 to 35 weight percent. Inanother embodiment, the acrylic or methacrylic acid is present in about8 to 35 weight percent, more preferably 8 to 25 weight percent, and mostpreferably 8 to 20 weight percent.

[0241] The ionomer also may include so-called “low acid” and “high acid”ionomers, as well as blends thereof. In general, ionic copolymersincluding up to about 15 percent acid are considered “low acid”ionomers, while those including greater than about 15 percent acid areconsidered “high acid” ionomers.

[0242] A low acid ionomer is believed to impart high spin. Thus, in oneembodiment, the intermediate layer includes a low acid ionomer where theacid is present in about 10 to 15 weight percent and optionally includesa softening comonomer, e.g., iso- or n-butylacrylate, to produce asofter terpolymer. The softening comonomer may be selected from thegroup consisting of vinyl esters of aliphatic carboxylic acids whereinthe acids have 2 to 10 carbon atoms, vinyl ethers wherein the alkylgroups contains 1 to 10 carbon atoms, and alkyl acrylates ormethacrylates wherein the alkyl group contains 1 to 10 carbon atoms.Suitable softening comonomers include vinyl acetate, methyl acrylate,methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate,butyl methacrylate, or the like.

[0243] In another embodiment, the intermediate layer includes at leastone high acid ionomer, for low spin rate and maximum distance. In thisaspect, the acrylic or methacrylic acid is present in about 15 to about35 weight percent, making the ionomer a high modulus ionomer. In oneembodiment, the high modulus ionomer includes about 16 percent by weightof a carboxylic acid, preferably from about 17 percent to about 25percent by weight of a carboxylic acid, more preferably from about 18.5percent to about 21.5 percent by weight of a carboxylic acid. In somecircumstances, an additional comonomer such as an acrylate ester (i.e.,iso- or n-butylacrylate, etc.) can also be included to produce a softerterpolymer. The additional comonomer may be selected from the groupconsisting of vinyl esters of aliphatic carboxylic acids wherein theacids have 2 to 10 carbon atoms, vinyl ethers wherein the alkyl groupscontains 1 to 10 carbon atoms, and alkyl acrylates or methacrylateswherein the alkyl group contains 1 to 10 carbon atoms. Suitablesoftening comonomers include vinyl acetate, methyl acrylate, methylmethacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butylmethacrylate, or the like.

[0244] Consequently, examples of a number of copolymers suitable for useto produce the high modulus ionomers include, but are not limited to,high acid embodiments of an ethylene/acrylic acid copolymer, anethylene/methacrylic acid copolymer, an ethylene/itaconic acidcopolymer, an ethylene/maleic acid copolymer, an ethylene/methacrylicacid/vinyl acetate copolymer, an ethylene/acrylic acid/vinyl alcoholcopolymer, and the like.

[0245] In one embodiment, the intermediate layer may be formed from atleast one polymer containing α,β-unsaturated carboxylic acid groups, orthe salts thereof, that have been 100 percent neutralized by organicfatty acids. The organic acids are aliphatic, mono-functional(saturated, unsaturated, or multi-unsaturated) organic acids. Salts ofthese organic acids may also be employed. The salts of organic acids ofthe present invention include the salts of barium, lithium, sodium,zinc, bismuth, chromium, cobalt, copper, potassium, strontium, titanium,tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin, orcalcium, salts of fatty acids, particularly stearic, bebenic, erucic,oleic, linoelic or dimerized derivatives thereof. It is preferred thatthe organic acids and salts of the present invention be relativelynon-migratory (they do not bloom to the surface of the polymer underambient temperatures) and non-volatile (they do not volatilize attemperatures required for melt-blending).

[0246] The acid moieties of the highly-neutralized polymers (“HNP”),typically ethylene-based ionomers, are preferably neutralized greaterthan about 70 percent, more preferably greater than about 90 percent,and most preferably at least about 100 percent. The HNP's may be also beblended with a second polymer component, which, if containing an acidgroup, may be neutralized in a conventional manner, by organic fattyacids, or both. The second polymer component, which may be partially orfully neutralized, preferably comprises ionomeric copolymers andterpolymers, ionomer precursors, thermoplastics, polyamides,polycarbonates, polyesters, polyurethanes, polyureas, thermoplasticelastomers, polybutadiene rubber, balata, metallocene-catalyzed polymers(grafted and non-grafted), single-site polymers, high-crystalline acidpolymers, cationic ionomers, and the like.

[0247] In this embodiment, the acid copolymers can be described as E/X/Ycopolymers where E is ethylene, X is an α,β-ethylenically unsaturatedcarboxylic acid, and Y is a softening comonomer. In a preferredembodiment, X is acrylic or methacrylic acid and Y is a C₁₋₈ alkylacrylate or methacrylate ester. X is preferably present in an amountfrom about 1 to about 35 weight percent of the polymer, more preferablyfrom about 5 to about 30 weight percent of the polymer, and mostpreferably from about 10 to about 20 weight percent of the polymer. Y ispreferably present in an amount from about 0 to about 50 weight percentof the polymer, more preferably from about 5 to about 25 weight percentof the polymer, and most preferably from about 10 to about 20 weightpercent of the polymer.

[0248] The organic acids are aliphatic, mono-functional (saturated,unsaturated, or multi-unsaturated) organic acids. Salts of these organicacids may also be employed. The salts of organic acids of the presentinvention include the salts of barium, lithium, sodium, zinc, bismuth,chromium, cobalt, copper, potassium, strontium, titanium, tungsten,magnesium, cesium, iron, nickel, silver, aluminum, tin, or calcium,salts of fatty acids, particularly stearic, bebenic, erucic, oleic,linoelic or dimerized derivatives thereof. It is preferred that theorganic acids and salts of the present invention be relativelynon-migratory (they do not bloom to the surface of the polymer underambient temperatures) and non-volatile (they do not volatilize attemperatures required for melt-blending).

[0249] Thermoplastic polymer components, such as copolyetheresters,copolyesteresters, copolyetheramides, elastomeric polyolefins, styrenediene block copolymers and their hydrogenated derivatives,copolyesteramides, thermoplastic polyurethanes, such ascopolyetherurethanes, copolyesterurethanes, copolyureaurethanes,epoxy-based polyurethanes, polycaprolactone-based polyurethanes,polyureas, and polycarbonate-based polyurethanes fillers, and otheringredients, if included, can be blended in either before, during, orafter the acid moieties are neutralized, thermoplastic polyurethanes.

[0250] Examples of these materials are disclosed in U.S. PatentApplication Publication Nos. 2001/0018375 and 2001/0019971, which areincorporated herein in their entirety by express reference thereto.

[0251] The ionomer compositions may also include at least one graftedmetallocene catalyzed polymers. Blends of this embodiment may includeabout 1 phr to about 100 phr of at least one grafted metallocenecatalyzed polymer and about 99 phr to 0 phr of at least one ionomer,preferably from about 5 phr to about 90 phr of at least one graftedmetallocene catalyzed polymer and about 95 phr to about 10 phr of atleast one ionomer, more preferably from about 10 phr to about 75 phr ofat least one grafted metallocene catalyzed polymer and about 90 phr toabout 25 phr of at least one ionomer, and most preferably from about 10phr to about 50 phr of at least one grafted metallocene catalyzedpolymer and about 90 phr to about 50 phr of at least one ionomer. Wherethe layer is foamed, the grafted metallocene catalyzed polymer blendsmay be foamed during molding by any conventional foaming or blowingagent.

[0252] In addition, polyamides, discussed in more detail below, may alsobe blended with ionomers.

[0253] The intermediate layer of inner cover layer as set forth abovecan also be comprised of more than one color. In a first embodiment, theintermediate layer can be formed by mixing a predetermined amount ofmaterial to form the intermediate layers and then dividing the materialinto two portions. Then an amount of pigment can be added to eachportion. The pigment can be different pigments or can different portionsof the same pigment. These portions then can be formed around the core.In one embodiment, the material can be divided and formed intohemispherical cups that are then compression molded over the core toform hemispheres of different colors. In another preferred embodiment,the material is divided into two portions and then co-injected over thecore or into hemispherical cups as set forth in U.S. Pat. No. 5,783,293and co-pending U.S. application Ser. No. 10/055,232, which areincorporated by reference herein in their entirety. However, it ispreferred that the amount of first material is reduced such that theco-injection process forms cups of different colors. Preferably, thefirst color covers between 10 and 90% of the surface of the intermediatelayer and the second color cover between 90 and 10%.

[0254] Non-Ionomeric Thermoplastic Materials

[0255] In another embodiment, the intermediate layer includes at leastone primarily or fully non-ionomeric thermoplastic material. Suitablenon-ionomeric materials include polyamides and polyamide blends, graftedand non-grafted metallocene catalyzed polyolefins or polyamides,polyamide/ionomer blends, polyamide/nonionomer blends, polyphenyleneether/ionomer blends, and mixtures thereof. Examples of grafted andnon-grafted metallocene catalyzed polyolefins or polyamides,polyamide/ionomer blends, polyamide/nonionomer blends are disclosed inco-pending U.S. patent application Ser. No. 10/138,304, filed May 6,2002, entitled “Golf Ball Incorporating Grafted Metallocene CatalyzedPolymer Blends,” the entire disclosure of which is incorporated byreference herein.

[0256] In one embodiment, polyamide homopolymers, such as polyamide 6,18and polyamide 6,36 are used alone, or in combination with otherpolyamide homopolymers. In another embodiment, polyamide copolymers,such as polyamide 6,10/6,36, are used alone, or in combination withother polyamide copolymers. Other examples of suitable polyamidehomopolymers and copolymers include polyamide polyamide 4, polyamide 6,polyamide 7, polyamide 11, polyamide 12 (manufactured as Rilsan AMNO byElf Atochem of Philadelphia, Pa.), polyamide 13, polyamide 4,6,polyamide 6,6, polyamide 6,9, polyamide 6,10, polyamide 6,12, polyamide6,36, polyamide 12,12, polyamide 13,13, polyamide 6/6,6, polyamide6,6/6,10, polyamide 6/6,T wherein T represents terephthalic acid,polyamide 6/6,6/6,10, polyamide 6,10/6,36, polyamide 66,6,18, polyamide66,6,36, polyamide 6/6,18, polyamide 6/6,36, polyamide 6/6,10/6,18,polyamide 6/6,10/6,36, polyamide 6,10/6,18, polyamide 6,12/6,18,polyamide 6,12/6,36, polyamide 6/66/6,18, polyamide 6/66/6,36, polyamide66/6,10/6,18, polyamide 66/6,10/6,36, polyamide 6/6,12/6,18, polyamide6/6,12/6,36, and mixtures thereof.

[0257] As mentioned above, any of the above polyamide homopolymer,copolymer, and homopolymer/copolymer blends may be optionally blendedwith nonionomer polymers, such as nonionomer thermoplastic polymers,nonionomer thermoplastic copolymers, nonionomer TPEs, and mixturesthereof.

[0258] One specific example of a polyamide-nonionomer blend is apolyamide-metallocene catalyzed polymer blend. The blended compositionsmay include grafted and/or non-grafted metallocene catalyzed polymers.Grafted metallocene catalyzed polymers, functionalized with pendantgroups, such as maleic anhydride, and the like, are available inexperimental quantities from DuPont. Grafted metallocene catalyzedpolymers may also be obtained by subjecting a commercially availablenon-grafted metallocene catalyzed polymer to a post-polymerizationreaction involving a monomer and an organic peroxide to provide agrafted metallocene catalyzed polymer with the desired pendant group orgroups.

[0259] Another example of a polyamide-nonionomer blend is a polyamideand non-ionic polymers produced using non-metallocene single-sitecatalysts. As used herein, the term “non-metallocene catalyst” ornon-metallocene single-site catalyst” refers to a single-site catalystother than a metallocene catalyst. Examples of suitable single-sitecatalyzed polymers are disclosed in co-pending U.S. patent applicationSer. No. 09/677,871, of which the entire disclosure is incorporated byreference herein.

[0260] Nonionomers suitable for blending with the polyamide include, butare not limited to, block copoly(ester) copolymers, block copoly(amide)copolymers, block copoly(urethane) copolymers, styrene-based blockcopolymers, thermoplastic and elastomer blends wherein the elastomer isnot vulcanized (TEB), and thermoplastic and elastomer or rubber blendswherein the elastomer is dynamically vulcanized (TED). Other nonionomerssuitable for blending with polyamide to form an intermediate layercomposition include, but are not limited to, polycarbonate,polyphenylene oxide, imidized, amino group containing polymers, highimpact polystyrene (HIPS), polyether ketone, polysulfone, poly(phenylenesulfide), reinforced engineering plastics,acrylic-styrene-acrylonitrile, poly(tetrafluoroethylene), poly(butylacrylate), poly(4-cyanobutyl acrylate), poly(2-ethylbutyl acrylate),poly(heptyl acrylate), poly(2-methylbutyl acrylate), poly(3-methylbutylacrylate), poly(N-octadecylacrylamide), poly(octadecyl methacrylate),poly(4-dodecylstyrene), poly(4-tetradecylstyrene), poly(ethylene oxide),poly(oxymethylene), poly(silazane), poly(furan tetracarboxylic aciddiimide), poly(acrylonitrile), poly(″-methylstyrene), as well as theclasses of polymers to which they belong and their copolymers, includingfunctional comonomers, and blends thereof.

[0261] In one embodiment, the non-ionomeric materials have a hardness ofabout 60 Shore D or greater and a flexural modulus of about 30,000 psior greater.

[0262] The intermediate layer may also be formed from the compositionsas disclosed in U.S. Pat. No. 5,688,191, the entire disclosure of whichis incorporated by reference herein, which are listed in Table 2 below.TABLE 2 INTERMEDIATE LAYER COMPOSITIONS AND PROPERTIES Flex TensileHardness Modulus Modulus % Strain Sample (Shore D) Resilience (psi)(psi) at Break 1A 0% Estane 58091 28 54 1,720 756 563 100% Estane 588611B 25% Estane 34 41 2,610 2,438 626 58091 75% Estane 58861 1C 50% Estane44 31 10,360 10,824 339 58091 50% Estane 58861 1D 75% Estane 61 3443,030 69,918 149 58091 25% Estane 58861 1E 100% Estane 78 46 147,240211,288 10 58091 0% Estane 58861 2A 0% Hytrel 5556 40 47 8,500 7,071 527100% Hytrel 4078 2B 25% Hytrel 5556 43 51 10,020 9,726 441 75% Hytrel4078 2C 50% Hytrel 5556 45 47 12,280 10,741 399 50% Hytrel 4078 2D 75%Hytrel 5556 48 53 13,680 13,164 374 25% Hytrel 4078 2E 100% Hytrel 48 5212,110 15,231 347 5556 0% Hytrel 4078 3A 0% Hytrel 5556 30 62 3,2402,078 810 100% Hytrel no break 3078 3B 25% Hytrel 5556 37 59 8,170 5,122685 75% Hytrel 3078 3C 50% Hytrel 5556 44 55 15,320 10,879 590 50%Hytrel 3078 3D 75% Hytrel 5556 53 50 19,870 16,612 580 25% Hytrel 30783E 100% Hytrel 58 50 54,840 17,531 575 5556 0% Hytrel 3078 4A 0% Hytrel4078 46 51 11,150 8,061 597 100% Pebax 4033 4B 25% Hytrel 4078 46 5310,360 7,769 644 75% Pebax 4033 4C 50% Hytrel 4078 45 52 9,780 8,117 56450% Pebax 4033 4D 75% Hytrel 4078 42 53 9,310 7,996 660 25% Pebax 40334E 100% Hytrel 40 51 9,250 6,383 531 3078 0% Pebax 4033 5A 0% Hytrel3078 77 50 156,070 182,869 9 100% Estane 58091 5B 25% Hytrel 3078 65 4887,680 96,543 33 75% Estane 58091 5C 50% Hytrel 3078 52 49 53,940 48,941102 50% Estane 58091 5D 75% Hytrel 3078 35 54 12,040 6,071 852 25%Estane 58091 5E 100% Hytrel 29 50 3,240 2,078 810 3078 0% no breakEstane 58091 6A 100% Kraton 29 59 24,300 29,331 515 1921 0% Estane 580910% Surlyn 7940 6B 50% Kraton 1921 57 49 56,580 — 145 50% Estane 58091 0%Surlyn 7940 6C 50% Kraton 1921 56 55 28,290 28,760 295 0% Estane 5809150% Surlyn 7940 7A 33.3% Pebax 48 50 41,240 30,032 294 4033 33.3% Estane58091 33.3% Hytrel 3078 7B 30% Pebax 4033 48 50 30,650 14,220 566 40%Estane 58091 10% Hytrel 3078 7C 20% Pebax 4033 41 54 24,020 16,630 51240% Estane 58091 40% Hytrel 3078

[0263] Golf Ball Construction

[0264] The compositions of the present invention may be used with manytypes of ball construction. For example, the ball may have a three-piecedesign, a double core, a double cover, multiple intermediate layers, amulti-layer core, and/or a multi-layer cover depending on the type ofperformance desired of the ball. As used herein, the term “multilayer”means at least two layers. For example, the compositions of theinvention may be used in a core, intermediate layer, and/or cover of agolf ball, each of which may have a single layer or multiple layers.

[0265] As described above in the core section, a core may be a one-piececore or a multilayer core, both of which may be solid, semi-solid,hollow, fluid-filled, or powder-filled. A multilayer core is one thathas an innermost component with an additional core layer or additionalcore layers disposed thereon. For example, FIG. 1 shows a golf ball 1having a core 2 and a cover 3. In one embodiment, the golf ball of FIG.1 represents a core 2 of polybutadiene reaction material, otherconventional materials or thermoplastic materials and a cover 3including the translucent polyurethane or polyurea composition of theinvention. In another embodiment, the golf ball of FIG. 1 represents acore 2 formed from polybutadiene reaction material with an opticallyactive chemical additive and a cover 3 including the transparentpolyurethane or polyurea composition of the invention.

[0266] In addition, when the golf ball of the present invention includesan intermediate layer, such as an inner cover layer or outer core layer,i.e., any layer(s) disposed between the inner core and the outer coverof a golf ball, this layer may be incorporated, for example, with asingle layer or a multilayer cover, with a one-piece core or amultilayer core, with both a single layer cover and core, or with both amultilayer cover and a multilayer core. As with the core, theintermediate layer may also include a plurality of layers. It will beappreciated that any number or type of intermediate layers may be used,as desired.

[0267]FIG. 2 illustrates a multilayer golf ball 11, including a cover13, at least one intermediate layer 14, and a core 12. In oneembodiment, the golf ball 11 of FIG. 2 may include a core 12 ofpolybutadiene reaction material, an intermediate layer 14, and a cover13 formed of the translucent composition of the invention. In addition,the golf ball 21 of FIG. 3 has a core 22 of polybutadiene reactionmaterial or other conventional core materials, at least one ionomerintermediate layer 24 with an optically active chemical additive, and atranslucent cover 23.

[0268] The intermediate layer may also be a tensioned elastomericmaterial wound around a solid, semi-solid, hollow, fluid-filled, orpowder-filled center. A wound layer may be described as a core layer oran intermediate layer for the purposes of the invention. As an example,the golf ball 31 of FIG. 4 may include a core layer 32, a tensionedelastomeric layer 34 wound thereon, and a cover layer 33. In particular,the golf ball 31 of FIG. 4 may have a core 32 made of a polybutadienereaction product, an intermediate layer including a tensionedelastomeric material 34 and cover 33 including at least one translucentpolyurethane or polyurea. The tensioned elastomeric material may beformed of any suitable material known to those of ordinary skill in theart, but is preferrably a wound layer such as that in U.S. Pat. No.6,149,535 which is incorporated by reference herein.

[0269] In one embodiment, the tensioned elastomeric layer is a hightensile filament having a tensile modulus of about 10,000 kpsi orgreater, as disclosed in co-pending U.S. patent application Ser. No.09/842,829, filed Apr. 27, 2001, entitled “All Rubber Golf Ball withHoop-Stress Layer,” the entire disclosure of which is incorporated byreference herein. In another embodiment, the tensioned elastomeric layeris coated with a binding material that will adhere to the core anditself when activated, causing the strands of the tensioned elastomericlayer to swell and increase the cross-sectional area of the layer by atleast about 5 percent. An example of such a golf ball construction isprovided in co-pending U.S. patent application Ser. No. 09/841,910, theentire disclosure of which is incorporated by reference herein.

[0270] The intermediate layer may also be formed of a binding materialand an interstitial material distributed in the binding material,wherein the effective material properties of the intermediate layer areuniquely different for applied forces normal to the surface of the ballfrom applied forces tangential to the surface of the ball. Examples ofthis type of intermediate layer are disclosed in U.S. patent applicationSer. No. 10/028,826, filed Dec. 28, 2001, entitled, “Golf Ball with aRadially Oriented Transversely Isotropic Layer and Manufacture of Same,”the entire disclosure of which is incorporated by reference herein. Inone embodiment of the present invention, the interstitial material mayextend from the intermediate layer into the core. In an alternativeembodiment, the interstitial material can also be embedded in the cover,or be in contact with the inner surface of the cover, or be embeddedonly in the cover such that it can be seen there-through.

[0271] At least one intermediate layer may also be a moisture barrierlayer, such as the ones described in U.S. Pat. No. 5,820,488, which isincorporated by reference herein. Any suitable film-forming materialhaving a lower water vapor transmission rate than the other layersbetween the core and the outer surface of the ball, i.e., cover, primer,and clear coat. Examples include, but are not limited to polyvinylidenechloride, vermiculite, and a polybutadiene reaction product withfluorine gas. In one embodiment, the moisture barrier layer has a watervapor transmission rate that is sufficiently low to reduce the loss ofCOR of the golf ball by at least 5 percent if the ball is stored at 100°F. and 70 percent relative humidity for six weeks as compared to theloss in COR of a golf ball that does not include the moisture barrier,has the same type of core and cover, and is stored under substantiallyidentical conditions.

[0272] Prior to forming the cover layer, the inner ball, i.e., the coreand any intermediate layers disposed thereon, may be surface treated toincrease the adhesion between the outer surface of the inner ball andthe cover. Examples of such surface treatment may include mechanicallyor chemically abrading the outer surface of the subassembly.Additionally, the inner ball may be subjected to corona discharge orplasma treatment prior to forming the cover around it. Other layers ofthe ball, e.g., the core, also may be surface treated. Examples of theseand other surface treatment techniques can be found in U.S. Pat. No.6,315,915, which is incorporated by reference in its entirety.

[0273] While hardness gradients are typically used in a golf ball toachieve certain characteristics, the present invention also contemplatesthe compositions of the invention being used in a golf ball withmultiple cover layers having essentially the same hardness, wherein atleast one of the layers has been modified in some way to alter aproperty that affects the performance of the ball. Such ballconstructions are disclosed in co-pending U.S. patent application Ser.No. 10/167,744, filed Jun. 13, 2002, entitled “Golf Ball with MultipleCover Layers,” the entire disclosure of which is incorporated byreference herein.

[0274] In one such embodiment, both covers layers can be formed of thesame material and have essentially the same hardness, but the layers aredesigned to have different coefficient of friction values. In anotherembodiment, the compositions of the invention are used in a golf ballwith multiple cover layers having essentially the same hardness, butdifferent rheological properties under high deformation. Another aspectof this embodiment relates to a golf ball with multiple cover layershaving essentially the same hardness, but different thicknesses tosimulate a soft outer cover over hard inner cover ball.

[0275] In another aspect of this concept, the cover layers of a golfball have essentially the same hardness, but different properties athigh or low temperatures as compared to ambient temperatures. Inparticular, this aspect of the invention is directed to a golf ballhaving multiple cover layers wherein the outer cover layer compositionhas a lower flexural modulus at reduced temperatures than the innercover layer, while the layers retain the same hardness at ambient andreduced temperatures, which results in a simulated soft outer coverlayer over a hard inner cover layer feel. Certain compositions may havea much more stable flexural modulus at different temperatures thanionomer resins and thus, could be used to make an effectively “softer”layer at lower temperatures than at ambient or elevated temperatures.

[0276] Yet another aspect of this concept relates to a golf ball withmultiple cover layers having essentially the same hardness, butdifferent properties under wet conditions as compared to dry conditions.Wettability of a golf ball layer may be affected by surface roughness,chemical heterogeneity, molecular orientation, swelling, and interfacialtensions, among others. Thus, non-destructive surface treatments of agolf ball layer may aid in increasing the hydrophilicity of a layer,while highly polishing or smoothing the surface of a golf ball layer maydecrease wettability. U.S. Pat. Nos. 5,403,453 and 5,456,972 disclosemethods of surface treating polymer materials to affect the wettability,the entire disclosures of which are incorporated by reference herein. Inaddition, plasma etching, corona treating, and flame treating may beuseful surface treatments to alter the wettability to desiredconditions. Wetting agents may also be added to the golf ball layercomposition to modify the surface tension of the layer.

[0277] Thus, the differences in wettability of the cover layersaccording to the invention may be measured by a difference in contactangle. The contact angles for a layer may be from about 1° (lowwettability) to about 180° (very high wettability). In one embodiment,the cover layers have contact angles that vary by about 1° or greater.In another embodiment, the contact angles of the cover layer vary byabout 3° or greater. In yet another embodiment, the contact angles ofthe cover layers vary by about 5° or greater.

[0278] Other non-limiting examples of suitable types of ballconstructions that may be used with the present invention include thosedescribed in U.S. Pat. Nos. 6,056,842, 5,688,191, 5,713,801, 5,803,831,5,885,172, 5,919,100, 5,965,669, 5,981,654, 5,981,658, and 6,149,535, aswell as in Publication Nos. US2001/0009310 μl, US2002/0025862, andUS2002/0028885. The entire disclosures of these patents and publishedpatent applications are incorporated by reference herein.

[0279] Methods of Forming Layers

[0280] The golf balls of the invention may be formed using a variety ofapplication techniques such as compression molding, flip molding,injection molding, retractable pin injection molding, reaction injectionmolding (RIM), liquid injection molding (LIM), casting, vacuum forming,powder coating, flow coating, spin coating, dipping, spraying, and thelike. A method of injection molding using a split vent pin can be foundin co-pending U.S. patent application Ser. No. 09/742,435, filed Dec.22, 2000, entitled “Split Vent Pin for Injection Molding.” Examples ofretractable pin injection molding may be found in U.S. Pat. Nos.6,129,881, 6,235,230, and 6,379,138. These molding references areincorporated in their entirety by reference herein. In addition, achilled chamber, i.e., a cooling jacket, such as the one disclosed inU.S. patent application Ser. No. 09/717,136, filed Nov. 22, 2000,entitled “Method of Making Golf Balls” may be used to cool thecompositions of the invention when casting, which also allows for ahigher loading of catalyst into the system.

[0281] Conventionally, compression molding and injection molding areapplied to thermoplastic materials, whereas RIM, liquid injectionmolding, and casting are employed on thermoset materials. These andother manufacture methods are disclosed in U.S. Pat. Nos. 6,207,784,5,484,870, and, the disclosures of which are incorporated herein byreference in their entirety.

[0282] The cores of the invention may be formed by any suitable methodknown to those of ordinary skill in art. When the cores are formed froma thermoset material, compression molded is a particularly suitablemethod of forming the core. In a thermoplastic core embodiment, on theother hand, the cores may be injection molded.

[0283] For example, methods of converting the cis-isomer of thepolybutadiene resilient polymer core component to the trans-isomerduring a molding cycle are known to those of ordinary skill in the art.Suitable methods include single pass mixing (ingredients are addedsequentially), multi-pass mixing, and the like. The crosslinking agent,and any other optional additives used to modify the characteristics ofthe golf ball center or additional layer(s), may similarly be combinedby any type of mixing. Suitable mixing equipment is well known to thoseof ordinary skill in the art, and such equipment may include a Banburymixer, a two-roll mill, or a twin screw extruder. Suitable mixing speedsand temperatures are well-known to those of ordinary skill in the art,or may be readily determined without undue experimentation.

[0284] The mixture can be subjected to, e.g., a compression or injectionmolding process, and the molding cycle may have a single step of moldingthe mixture at a single temperature for a fixed-time duration. In oneembodiment, a single-step cure cycle is employed. Although the curingtime depends on the various materials selected, a suitable curing timeis about 5 to about 18 minutes, preferably from about 8 to about 15minutes, and more preferably from about 10 to about 12 minutes. Anexample of a single step molding cycle, for a mixture that containsdicumyl peroxide, would hold the polymer mixture at 171° C. (340° F.)for a duration of 15 minutes. An example of a two-step molding cyclewould be holding the mold at 143° C. (290° F.) for 40 minutes, thenramping the mold to 171° C. (340° F.) where it is held for a duration of20 minutes. Those of ordinary skill in the art will be readily able toadjust the curing time based on the particular materials used and thediscussion herein.

[0285] Furthermore, U.S. Pat. Nos. 6,180,040 and 6,180,722 disclosemethods of preparing dual core golf balls. The disclosures of thesepatents are hereby incorporated by reference in their entirety.

[0286] The intermediate layer may also be formed from using any suitablemethod known to those of ordinary skill in the art. For example, anintermediate layer may be formed by blow molding and covered with adimpled cover layer formed by injection molding, compression molding,casting, vacuum forming, powder coating, and the like.

[0287] The castable reactive liquid polyurethanes and polyurea materialsof the invention may be applied over the inner ball using a variety ofapplication techniques such as casting, injection molding spraying,compression molding, dipping, spin coating, or flow coating methods thatare well known in the art. In one embodiment, the castable reactivepolyurethanes and polyurea material is formed over the core using acombination of casting and compression molding. Conventionally,compression molding and injection molding are applied to thermoplasticcover materials, whereas RIM, liquid injection molding, and casting areemployed on thermoset cover materials.

[0288] U.S. Pat. No. 5,733,428, the entire disclosure of which is herebyincorporated by reference, discloses a method for forming a polyurethanecover on a golf ball core. Because this method relates to the use ofboth casting thermosetting and thermoplastic material as the golf ballcover, wherein the cover is formed around the core by mixing andintroducing the material in mold halves, the polyurea compositions mayalso be used employing the same casting process.

[0289] For example, once the polyurea composition is mixed, anexothermic reaction commences and continues until the material issolidified around the core. It is important that the viscosity bemeasured over time, so that the subsequent steps of filling each moldhalf, introducing the core into one half and closing the mold can beproperly timed for accomplishing centering of the core cover halvesfusion and achieving overall uniformity. A suitable viscosity range ofthe curing urea mix for introducing cores into the mold halves isdetermined to be approximately between about 2,000 cP and about 30,000cP, with the preferred range of about 8,000 cP to about 15,000 cP.

[0290] To start the cover formation, mixing of the prepolymer andcurative is accomplished in a motorized mixer inside a mixing head byfeeding through lines metered amounts of curative and prepolymer. Toppreheated mold halves are filled and placed in fixture units usingcentering pins moving into apertures in each mold. At a later time, thecavity of a bottom mold half, or the cavities of a series of bottom moldhalves, is filled with similar mixture amounts as used for the top moldhalves. After the reacting materials have resided in top mold halves forabout 40 to about 100 seconds, preferably for about 70 to about 80seconds, a core is lowered at a controlled speed into the gellingreacting mixture.

[0291] A ball cup holds the ball core through reduced pressure (orpartial vacuum). Upon location of the core in the halves of the moldafter gelling for about 4 to about 12 seconds, the vacuum is releasedallowing the core to be released. In one embodiment, the vacuum isreleased allowing the core to be released after about 5 seconds to 10seconds. The mold halves, with core and solidified cover half thereon,are removed from the centering fixture unit, inverted and mated withsecond mold halves which, at an appropriate time earlier, have had aselected quantity of reacting polyurea prepolymer and curing agentintroduced therein to commence gelling.

[0292] Similarly, U.S. Pat. No. 5,006,297 and U.S. Pat. No. 5,334,673both also disclose suitable molding techniques that may be utilized toapply the castable reactive liquids employed in the present invention.However, the method of the invention is not limited to the use of thesetechniques; other methods known to those skilled in the art may also beemployed. For instance, other methods for holding the ball core may beutilized instead of using a partial vacuum.

[0293] Dimples

[0294] The use of various dimple patterns and profiles provides arelatively effective way to modify the aerodynamic characteristics of agolf ball. As such, the manner in which the dimples are arranged on thesurface of the ball can be by any available method. For instance, theball may have an icosahedron-based pattern, such as described in U.S.Pat. No. 4,560,168, or an octahedral-based dimple patterns as describedin U.S. Pat. No. 4,960,281.

[0295] In one embodiment of the present invention, the golf ball has anicosahedron dimple pattern that includes 20 triangles made from about300-500 dimples and, except perhaps for the mold parting line, does nothave a great circle that does not intersect any dimples. Each of thelarge triangles, preferably, has an odd number of dimples (7) along eachside and the small triangles have an even number of dimples (4) alongeach side. To properly pack the dimples, the large triangle has ninemore dimples than the small triangle. In another embodiment, the ballhas at least five different sizes of dimples.

[0296] In one embodiment of the present invention, the golf ball has anoctahedron dimple pattern including eight triangles made from about 440dimples and three great circles that do not intersect any dimples. Inthe octahedron pattern, the pattern includes a third set of dimplesformed in a smallest triangle inside of and adjacent to the smalltriangle. To properly pack the dimples, the large triangle has nine moredimples than the small triangle and the small triangle has nine moredimples than the smallest triangle. In this embodiment, the ball has sixdifferent dimple diameters distributed over the surface of the ball. Thelarge triangle has five different dimple diameters, the small trianglehas three different dimple diameters and the smallest triangle has twodifferent dimple diameters.

[0297] Alternatively, the dimple pattern can be arranged according tophyllotactic patterns, such as described in U.S. Pat. No. 6,338,684,which is incorporated herein in its entirety.

[0298] Dimple patterns may also be based on Archimedean patternsincluding a truncated octahedron, a great rhombcuboctahedron, atruncated dodecahedron, and a great rhombicosidodecahedron, wherein thepattern has a non-linear parting line, as disclosed in U.S. patentapplication Ser. No. 10/078,417, which is incorporated by referenceherein.

[0299] The golf balls of the present invention may also be covered withnon-circular shaped dimples, i.e., amorphous shaped dimples, asdisclosed in U.S. Pat. No. 6,409,615, which is incorporated in itsentirety by reference herein.

[0300] Dimple patterns that provide a high percentage of surfacecoverage are preferred, and are well known in the art. For example, U.S.Pat. Nos. 5,562,552, 5,575,477, 5,957,787, 5,249,804, and 4,925,193disclose geometric patterns for positioning dimples on a golf ball. Inone embodiment, the golf balls of the invention have a dimple coverageof the surface area of the cover of at least about 60 percent,preferably at least about 65 percent, and more preferably at least 70percent or greater. Dimple patterns having even higher dimple coveragevalues may also be used with the present invention. Thus, the golf ballsof the present invention may have a dimple coverage of at least about 75percent or greater, about 80 percent or greater, or even about 85percent or greater.

[0301] In addition, a tubular lattice pattern, such as the one disclosedin U.S. Pat. No. 6,290,615, which is incorporated by reference in itsentirety herein, may also be used with golf balls of the presentinvention. The golf balls of the present invention may also have aplurality of pyramidal projections disposed on the intermediate layer ofthe ball, as disclosed in U.S. Pat. No. 6,383,092, which is incorporatedin its entirety by reference herein. The plurality of pyramidalprojections on the golf ball may cover between about 20 percent to about90 of the surface of the intermediate layer.

[0302] In an alternative embodiment, the golf ball may have a non-planarparting line allowing for some of the plurality of dimples orprojections to be disposed about the equator.

[0303] Several additional non-limiting examples of dimple patterns withvarying sizes of dimples are also provided in U.S. Pat. No. 6,213,898,the entire disclosures of which is incorporated by reference herein.

[0304] The total number of dimples on the ball, or dimple count, mayvary depending such factors as the sizes of the dimples and the patternselected. In general, the total number of dimples on the ball preferablyis between about 100 to about 1000 dimples, although one skilled in theart would recognize that differing dimple counts within this range cansignificantly alter the flight performance of the ball. In oneembodiment, the dimple count is about 300-360 dimples. In oneembodiment, the dimple count on the ball is about 360-400 dimples.

[0305] Dimple profiles revolving a catenary curve about its symmetricalaxis may increase aerodynamic efficiency, provide a convenient way toalter the dimples to adjust ball performance without changing the dimplepattern, and result in uniformly increased flight distance for golfersof all swing speeds. Thus, catenary curve dimple profiles, as disclosedin U.S. patent application Ser. No. 09/989,191, filed Nov. 21, 2001,entitled “Golf Ball Dimples with a Catenary Curve Profile,” which isincorporated in its entirety by reference herein, is contemplated foruse with the golf balls of the present invention.

[0306] Golf Ball Post-Processing

[0307] The golf balls of the present invention may be clear coated, orsurface treated for further benefits.

[0308] For example, golf balls covers frequently contain a fluorescentmaterial and/or a dye or pigment to achieve the desired colorcharacteristics. A golf ball of the invention may also be treated with abase resin composition, however, as disclosed in U.S. Patent PublicationNo. 2002/0082358, which includes a 7-triazinylamino-3-phenylcoumarinderivative as the fluorescent agent to provide improved weatherresistance and brightness.

[0309] In addition, trademarks or other indicia may be printed, i.e.,pad-printed or ink jet printed, on the outer surface of the ball cover,and the outer surface is then treated with at least one clear coat togive the ball a glossy finish and protect the indicia. Alternately, theindicia can be printed on the inner layer such that it is visiblethrough the translucent cover.

[0310] The golf balls of the invention may also be subjected to dyesublimation, wherein at least one golf ball component is subjected to atleast one sublimating ink that migrates at a depth into the outersurface and forms an indicia. The at least one sublimating inkpreferably includes at least one of an azo dye, a nitroarylamine dye, oran anthraquinone dye. U.S. patent application Ser. No. 10/012,538, filedDec. 12, 2001, entitled, “Method of Forming Indicia on a Golf Ball,” theentire disclosure of which is incorporated by reference herein.

[0311] Laser marking of a selected surface portion of a golf ballcausing the laser light-irradiated portion to change color is alsocontemplated for use with the present invention. U.S. Pat. Nos.5,248,878 and 6,075,223 generally disclose such methods, the entiredisclosures of which are incorporated by reference herein. In addition,the golf balls may be subjected to ablation, i.e., directing a beam oflaser radiation onto a portion of the cover or inner cover, irradiatingthe cover portion, wherein the irradiated cover portion is ablated toform a detectable mark, wherein no significant discoloration of thecover portion results therefrom. Ablation is discussed in U.S. patentapplication Ser. No. 09/739,469, filed Dec. 18, 2002, entitled “LaserMarking of Golf Balls,” which is incorporated in its entirety byreference herein.

[0312] Protective and decorative coating materials, as well as methodsof applying such materials to the surface of a golf ball cover are wellknown in the golf ball art. Generally, such coating materials compriseurethanes, urethane hybrids, epoxies, polyesters and acrylics. Ifdesired, more than one coating layer can be used. The coating layer(s)may be applied by any suitable method known to those of ordinary skillin the art. In one embodiment, the coating layer(s) is applied to thegolf ball cover by an in-mold coating process, such as described in U.S.Pat. No. 5,849,168, which is incorporated in its entirety by referenceherein.

[0313] Thus, while it is not desirable to use pigmented coating on thegolf balls of the present invention when formed with the translucentcompositions, the golf balls of the present invention may be painted,coated, or surface treated for further benefits. For example, the valueof golf balls made according to the invention and painted offer enhancedcolor stability as degradation of the surface paint occurs during thenormal course of play. The mainstream technique used nowadays forhighlighting whiteness is to form a cover toned white with titaniumdioxide, subjecting the cover to such surface treatment as coronatreatment, plasma treatment, UV treatment, flame treatment, or electronbeam treatment, and applying one or more layers of clear paint, whichmay contain a fluorescent whitening agent. This technique is productiveand cost effective.

[0314] Golf Ball Properties

[0315] The properties such as hardness, modulus, core diameter,intermediate layer thickness and cover layer thickness of the golf ballsof the present invention have been found to effect play characteristicssuch as spin, initial velocity and feel of the present golf balls. Forexample, the flexural and/or tensile modulus of the intermediate layerare believed to have an effect on the “feel” of the golf balls of thepresent invention.

[0316] Component Dimensions

[0317] Dimensions of golf ball components, i.e., thickness and diameter,may vary depending on the desired properties. For the purposes of theinvention, any layer thickness may be employed. Non-limiting examples ofthe various embodiments outlined above are provided here with respect tolayer dimensions.

[0318] The present invention relates to golf balls of any size. WhileUSGA specifications limit the size of a competition golf ball to morethan 1.68 inches in diameter, golf balls of any size can be used forleisure golf play. The preferred diameter of the golf balls is fromabout 1.68 inches to about 1.8 inches. The more preferred diameter isfrom about 1.68 inches to about 1.76 inches. A diameter of from about1.68 inches to about 1.74 inches is most preferred, however diametersanywhere in the range of from 1.7 to about 1.95 inches can be used.Preferably, the overall diameter of the core and all intermediate layersis about 80 percent to about 98 percent of the overall diameter of thefinished ball.

[0319] The core may have a diameter ranging from about 0.09 inches toabout 1.65 inches. In one embodiment, the diameter of the core of thepresent invention is about 1.2 inches to about 1.630 inches. In anotherembodiment, the diameter of the core is about 1.3 inches to about 1.6inches, preferably from about 1.39 inches to about 1.6 inches, and morepreferably from about 1.5 inches to about 1.6 inches. In yet anotherembodiment, the core has a diameter of about 1.55 inches to about 1.65inches.

[0320] The core of the golf ball may also be extremely large in relationto the rest of the ball. For example, in one embodiment, the core makesup about 90 percent to about 98 percent of the ball, preferably about 94percent to about 96 percent of the ball. In this embodiment, thediameter of the core is preferably about 1.54 inches or greater,preferably about 1.55 inches or greater. In one embodiment, the corediameter is about 1.59 to 1.64 inches.

[0321] When the core includes an inner core layer and an outer corelayer, the inner core layer is preferably about 0.09 inches or greaterand the outer core layer preferably has a thickness of about 0.1 inchesor greater. In one embodiment, the inner core layer has a diameter fromabout 0.09 inches to about 1.2 inches and the outer core layer has athickness from about 0.1 inches to about 0.8 inches. In yet anotherembodiment, the inner core layer diameter is from about 0.095 inches toabout 1.1 inches and the outer core layer has a thickness of about 0.2inches to about 0.3 inches.

[0322] The cover typically has a thickness to provide sufficientstrength, good performance characteristics, and durability. In oneembodiment, the cover thickness is from about 0.02 inches to about 0.35inches. The cover preferably has a thickness of about 0.02 inches toabout 0.12 inches, preferably about 0.1 inches or less. When thecompositions of the invention are used to form the outer cover of a golfball, the cover may have a thickness of about 0.1 inches or less,preferably about 0.07 inches or less. In one embodiment, the outer coverhas a thickness from about 0.02 inches to about 0.07 inches. In anotherembodiment, the cover thickness is about 0.05 inches or less, preferablyfrom about 0.02 inches to about 0.05 inches. In yet another embodiment,the outer cover layer of such a golf ball is between about 0.02 inchesand about 0.045 inches. In still another embodiment, the outer coverlayer is about 0.025 to about 0.04 inches thick. In one embodiment, theouter cover layer is about 0.03 inches thick.

[0323] The range of thicknesses for an intermediate layer of a golf ballis large because of the vast possibilities when using an intermediatelayer, i.e., as an outer core layer, an inner cover layer, a woundlayer, a moisture/vapor barrier layer. When used in a golf ball of theinvention, the intermediate layer, or inner cover layer, may have athickness about 0.3 inches or less. In one embodiment, the thickness ofthe intermediate layer is from about 0.002 inches to about 0.1 inches,preferably about 0.01 inches or greater. In one embodiment, thethickness of the intermediate layer is about 0.09 inches or less,preferably about 0.06 inches or less. In another embodiment, theintermediate layer thickness is about 0.05 inches or less, morepreferably about 0.01 inches to about 0.045 inches. In one embodiment,the intermediate layer, thickness is about 0.02 inches to about 0.04inches. In another embodiment, the intermediate layer thickness is fromabout 0.025 inches to about 0.035 inches. In yet another embodiment, thethickness of the intermediate layer is about 0.035 inches thick. Instill another embodiment, the inner cover layer is from about 0.03inches to about 0.035 inches thick. Varying combinations of these rangesof thickness for the intermediate and outer cover layers may be used incombination with other embodiments described herein.

[0324] The ratio of the thickness of the intermediate layer to the outercover layer is preferably about 10 or less, preferably from about 3 orless. In another embodiment, the ratio of the thickness of theintermediate layer to the outer cover layer is about 1 or less.

[0325] The core and intermediate layer(s) together form an inner ballpreferably having a diameter of about 1.48 inches or greater for a1.68-inch ball. In one embodiment, the inner ball of a 1.68-inch ballhas a diameter of about 1.52 inches or greater. In another embodiment,the inner ball of a 1.68-inch ball has a diameter of about 1.66 inchesor less. In yet another embodiment, a 1.72-inch (or more) ball has aninner ball diameter of about 1.50 inches or greater. In still anotherembodiment, the diameter of the inner ball for a 1.72-inch ball is about1.70 inches or less.

[0326] Hardness

[0327] Most golf balls consist of layers having different hardnesses,e.g., hardness gradients, to achieve desired performancecharacteristics. The present invention contemplates golf balls havinghardness gradients between layers, as well as those golf balls withlayers having the same hardness.

[0328] It should be understood, especially to one of ordinary skill inthe art, that there is a fundamental difference between “materialhardness” and “hardness, as measured directly on a golf ball.” Materialhardness is defined by the procedure set forth in ASTM-D2240 andgenerally involves measuring the hardness of a flat “slab” or “button”formed of the material of which the hardness is to be measured.Hardness, when measured directly on a golf ball (or other sphericalsurface) is a completely different measurement and, therefore, resultsin a different hardness value. This difference results from a number offactors including, but not limited to, ball construction (i.e., coretype, number of core and/or cover layers, etc.), ball (or sphere)diameter, and the material composition of adjacent layers. It shouldalso be understood that the two measurement techniques are not linearlyrelated and, therefore, one hardness value cannot easily be correlatedto the other.

[0329] The cores of the present invention may have varying hardnessesdepending on the particular golf ball construction. In one embodiment,the core hardness is at least about 15 Shore A, preferably about 30Shore A, as measured on a formed sphere. In another embodiment, the corehas a hardness of about 50 Shore A to about 90 Shore D. Preferably, thecore has a hardness about 30 to about 65 Shore D, and more preferably,the core has a hardness about 35 to about 60 Shore D.

[0330] The intermediate layer(s) of the present invention may also varyin hardness depending on the specific construction of the ball. In oneembodiment, the hardness of the intermediate layer is about 30 Shore Dor greater. In another embodiment, the hardness of the intermediatelayer is about 90 Shore D or less, preferably about 80 Shore D or less,and more preferably about 70 Shore D or less. In yet another embodiment,the hardness of the intermediate layer is about 50 Shore D or greater,preferably about 55 Shore D or greater. In one embodiment, theintermediate layer hardness is from about 55 Shore D to about 70 ShoreD.

[0331] When the intermediate layer is intended to be harder than thecore layer, the ratio of the intermediate layer hardness to the corehardness preferably about 2 or less. In one embodiment, the ratio isabout 1.8 or less. In yet another embodiment, the ratio is about 1.3 orless.

[0332] As with the core and intermediate layers, the cover hardness mayvary depending on the construction and desired characteristics of thegolf ball. The ratio of cover hardness to inner ball hardness is aprimary variable used to control the aerodynamics of a ball and, inparticular, the spin of a ball. In general, the harder the inner ball,the greater the driver spin and the softer the cover, the greater thedriver spin.

[0333] For example, when the intermediate layer is intended to be thehardest point in the ball, e.g., about 50 Shore D to about 75 Shore D,the cover material may have a hardness of about 20 Shore D or greater,preferably about 25 Shore D or greater, and more preferably about 30Shore D or greater, as measured on the slab. In another embodiment, thecover itself has a hardness of about 30 Shore D or greater. Inparticular, the cover may be from about 30 Shore D to about 62 Shore D.In one embodiment, the cover has a hardness of about 40 Shore D to about65 Shore D. In another embodiment, the cover has a hardness less thanabout 60 Shore D.

[0334] In this embodiment when the outer cover layer is softer than theintermediate layer or inner cover layer, the ratio of the Shore Dhardness of the outer cover material to the intermediate layer materialis about 0.8 or less, preferably about 0.75 or less, and more preferablyabout 0.7 or less.

[0335] In yet another embodiment, the cover and intermediate layermaterials have hardnesses that are substantially the same. When thehardness differential between the cover layer and the intermediate layeris not intended to be as significant, the cover may have a hardness ofabout 55 Shore D to about 65 Shore D. In this embodiment, the ratio ofthe Shore D hardness of the outer cover to the intermediate layer isabout 1.0 or less, preferably about 0.8 to 1.0 or less.

[0336] The cover hardness may also be defined in terms of Shore C. Forexample, the cover may have a hardness of about 70 Shore C or greater,preferably about 80 Shore C or greater. In another embodiment, the coverhas a hardness of about 95 Shore C or less, preferably about 90 Shore Cor less.

[0337] In another embodiment, the cover layer is harder than theintermediate layer. In this design, the ratio of Shore D hardness of thecover layer to the intermediate layer is about 1.33 or less, preferablyfrom about 1.14 or less.

[0338] When a two-piece ball is constructed, the core may be softer thanthe outer cover. For example, the core hardness may range from about 30Shore D to about 50 Shore D, and the cover hardness may be from about 50Shore D to about 80 Shore D. In this type of construction, the ratiobetween the cover hardness and the core hardness is preferably about1.75 or less. In another embodiment, the ratio is about 1.55 or less.Depending on the materials, for example, if a composition of theinvention is acid-functionalized wherein the acid groups are at leastpartially neutralized, the hardness ratio of the cover to core ispreferably about 1.25 or less.

[0339] Compression

[0340] Compression values are dependent on the diameter of the componentbeing measured. The Atti compression of the core, or portion of thecore, of golf balls prepared according to the invention is preferablyless than about 80, more preferably less than about 75. As used herein,the terms “Atti compression” or “compression” are defined as thedeflection of an object or material relative to the deflection of acalibrated spring, as measured with an Atti Compression Gauge, that iscommercially available from Atti Engineering Corp. of Union City, N.J.Atti compression is typically used to measure the compression of a golfball. In another embodiment, the core compression is from about 40 toabout 80, preferably from about 50 to about 70. In yet anotherembodiment, the core compression is preferably below about 40.

[0341] In an alternative, low compression embodiment, the core has ainner component with compression less than about 20, more preferablyless than about 10, and most preferably, 0. As known to those ofordinary skill in the art, however, the cores generated according to thepresent invention may be below the measurement of the Atti CompressionGauge.

[0342] In one embodiment, golf balls of the invention preferably have anAtti compression about 90 to about 120.

[0343] Initial Velocity and COR

[0344] There is currently no USGA limit on the COR of a golf ball, butthe initial velocity of the golf ball cannot exceed 250±5 feet/second(ft/s). Thus, in one embodiment, the initial velocity is about 245 ft/sto about 255 ft/s. In another embodiment, the initial velocity is about250 ft/s or greater. In one embodiment, the initial velocity is about253 ft/s to about 254 ft/s. In yet another embodiment, the initialvelocity is greater than about 255 ft/s. While the current rules oninitial velocity require that golf ball manufacturers stay within thelimit, one of ordinary skill in the art would appreciate that the golfball of the invention would readily convert into a golf ball withinitial velocity outside of this range.

[0345] The present invention contemplates golf balls having CORsmeasured at 125 ft/sec from about 0.7 to about 0.85. In one embodiment,the COR is about 0.75 or greater, preferably about 0.78 or greater. Inanother embodiment, the ball has a COR of about 0.8 or greater.Preferably, the COR at 125 ft/sec is between about 0.81 and 0.85.

[0346] In addition, the ball preferably has a COR at 143 ft/sec of about0.780 or more. In one embodiment, the COR is between about 0.78 and0.84.

[0347] Flexural Modulus

[0348] Accordingly, it is preferable that the golf balls of the presentinvention have an intermediate layer with a flexural modulus of about500 psi to about 500,000 psi. More preferably, the flexural modulus ofthe intermediate layer is about 10,000 psi to about 100,000 psi. Mostpreferably, the flexural modulus of the intermediate layer is about50,000 psi to about 100,000 psi.

[0349] The flexural moduli of the cover layer is preferably about 2,000psi or greater, and more preferably about 5,000 psi or greater. In oneembodiment, the flexural modulus of the cover is from about 10,000 psito about 30,000 psi. More preferably, the flexural modulus of the coverlayer is about 15,000 psi to about 30,000 psi.

[0350] In another embodiment, the flexural moduli of the cover layer isabout 100,000 psi or less, preferably about 80,000 or less, and morepreferably about 70,000 psi or less. In one embodiment, when the coverlayer has a hardness of about 50 Shore D to about 60 Shore D, the coverlayer preferably has a flexural modulus of about 55,000 psi to about65,000 psi.

[0351] In one embodiment, the ratio of the flexural modulus of theintermediate layer to the cover layer is about 0.003 to about 50. Inanother embodiment, the ratio of the flexural modulus of theintermediate layer to the cover layer is about 0.006 to about 4.5. Inyet another embodiment, the ratio of the flexural modulus of theintermediate layer to the cover layer is about 0.11 to about 4.5.

[0352] In one embodiment, the compositions of the invention are used ina golf ball with multiple cover layers having essentially the samehardness, but differences in flexural moduli. In this aspect of theinvention, the difference between the flexural moduli of the two coverlayers is preferably between about 500 and 5,000 psi.

[0353] Adhesion Strength

[0354] The adhesion, or peel, strength of the cover compositions of theinvention is preferably about 5 lb_(f)/in or greater. Preferably, theadhesion strength is about 20 lb_(f)/in or greater.

[0355] Light Stability

[0356] The light stability of the cover may be quantified by thedifference in yellowness index (*Y1), i.e., yellowness measured after apredetermined exposure time−yellowness before exposure. In oneembodiment, the *Y1 is about 10 or less after 5 days (120 hours) ofexposure, preferably about 6 or less after 5 days of exposure, and morepreferably about 4 or less after 5 days of exposure. In one embodiment,the *Y1 is about 2 or less after 5 days of exposure, and more preferablyabout 1 or less after 5 days of exposure. The difference in the b chromadimension (*b*, yellow to blue) is also a way to quantify the lightstability of the cover. In one embodiment, the *b* is about 4 or lessafter 5 days (120 hours) of exposure, preferably about 3 or less after 5days of exposure, and more preferably about 2 or less after 5 days ofexposure. In one embodiment, the *b* is about 1 or less after 5 days ofexposure.

[0357] The term “about,” as used herein in connection with one or morenumbers or numerical ranges, should be understood to refer to all suchnumbers, including all numbers in a range.

[0358] As used herein, the term “polyurethane composition” refers to acombination of the reaction product of a prepolymer including at leastone polyisocyanate and at least one polyol, and at least one curingagent, in addition to the color stabilizer component.

[0359] As used herein, the term “ATTI compression” is defined as thedeflection of an object or material relative to the deflection of acalibrated spring, as measured with an Atti Compression Gauge, that iscommercially available from Atti Engineering Corp. of Union City, N.J.ATTI compression is typically used to measure the compression of a golfball. However, when referring to the compression of a core, it ispreferred to use a compressive load measurement.

EXAMPLES

[0360] The following example is provided for illustrative purposes onlyand is not to be construed as limiting the scope of the invention in anymanner.

Example 1 Polyurethane Golf Ball Covers

[0361] The first golf ball prepared according to the invention has anouter cover layer formed of the polyurethane composition of the presentinvention including a reaction product of 4,4′-diphenylmethanediisocyanate (“MDI”), polytetramethylene ether glycol (“PTMEG”) orpolycapralactone, a mixture of 3,5-dimethylthio-2,4-toluenediamine and3,5-dimethylthio-2,6-toluenediamine curatives (Ethacure 300) or1,4-butaindiol curatives, and UV stabilizers TINUVIN 571 and TINUVIN765. The golf ball's outer cover layer was prepared according to thegolf ball formation methods described in U.S. Pat. Nos. 5,733,428 and5,888,437, which are incorporated in their entirety herein by reference.

[0362] The inner cover or intermediate layer was comprised of a blend ofionomers with flourescent yellow pigment. Preferably, the inner covercan be comprised of an ionomer blend such as SURLYN 7940 and 8945 andbetween 1 and 10% by weight of Solvent Yellow 44. An favorable examplewas made with 5% Solvent Yellow 44.

[0363] The cover of the embodiment was about 0.035 inches thick and theinner cover of intermediate layer was about 0.03 inches thick. Thesewere formed on a 1.55″ core as set forth above.

Example 2 H₁₂MDI Polyether Urea Golf Ball Covers

[0364] A golf ball can be made having the cover formulated from acomposition including a prepolymer formed of H₁₂MDI and polyoxyalkylene,having a molecular weight of about 2000, cured with4,4′-bis-(sec-butylamino)-dicyclohexylmethane (Clearlink 1000). A golfball inner cover and core similar to Example 1 is preferred. TABLE 9PHYSICAL PROPERTIES OF BALLS ACCORDING TO EXAMPLES 1 AND 2 BallProperties/Ball Types Polyurethane Polyurea Nameplate Average 1.6831.686 Equator Average 1.681 1.684 Weight Average, oz 1.597 1.600Compression Average 89 92 CoR @ 125 ft/sec 0.807 0.815 Cold Crack Test,5° F. no failure no failure

Example 3 H₁₂MDI Polyether Urea Golf Ball Covers

[0365] Another preferred embodiment is a golf ball like that in Example2, but with an outer cover of the formula set forth above with theaddition of between about 0.003 and 0.03% blue optical brightner such asDayGlo blue A-19. For a light blue hint, 0.003% can be used and for atrue blue highlight, 0.01% blue can be added. In this example, the innercover preferably comprises about 5% white pigment.

Example 4 H₁₂MDI Polyether Urea Golf Ball Covers

[0366] Another preferred embodiment is a three piece golf ball with anouter cover of the formula set forth in Example 2 with the addition ofbetween about 0.001 and 0.01% pearlescent or iridescent pigment such asthe Mearlin Luster Pigments available from Mearl. In this embodiment,the inner cover or intermediate layer preferably comprises about 5%white pigment.

Example 5 Ionomer Golf Ball Covers

[0367] Another preferred embodiment is a three piece golf ball with anouter cover comprised of a blend of ionomer(s) or ionomers withMetallocene or Nucrel with the addition of between about 0.001 and 0.01%pearlescent or iridescent pigment such Mearlin Luster Pigments availablefrom Mearl. In this example, the inner cover preferably comprises about5% white pigment.

[0368] For example, the inner cover or intermediate layer can comprise ablend of ionomer resins such as SURLYN 8528 and 9650 with about 5% whitecolor concentrate. The outer cover can comprise a blend of Fuseabond(Metallocene) SURLYN 7940 and 8945 and 0.001% pearlescent pigment.

Example 6 Ionomer Golf Ball Covers

[0369] Another preferred embodiment is an outer cover comprised of ablend of ionomer(s) or ionomer(s) with Metallocene or Nucrel with theaddition of between about 0.001 and 0.01% blue optical brightner. Inthis example, the inner cover preferably comprises about 5% whitepigment.

[0370] In this embodiment, the inner cover can comprise a blend ofionomer resins such as SURLYN 8528 and 9650 with about 5% white colorconcentrate. The outer cover can comprise a blend of Fuseabond(Metallocene), SURLYN 7940 and 8945 and 0.003% DayGlo blue A-19. Anotherembodiment with a deeper blue color can comprise about 0.006% DayGloblue A-19.

Example 7 Polyurethane/Polyurea Multi-Color Golf Ball Covers

[0371] The first golf ball prepared according to this embodiment has aoptically clear or substantially clear outer cover layer formed of apolyurethane or polyurea composition. The outer cover of the presentinvention can be comprised of a reaction product of 4,4′-diphenylmethanediisocyanate (“MDI”), polytetramethylene ether glycol (“PTMEG”) orpolycapralactone, a mixture of 3,5-dimethylthio-2,4-toluenediamine and3,5-dimethylthio-2,6-toluenediamine curatives (Ethacure 300) or1,4-butaindiol curatives, and UV stabilizers such as TINUVIN 571 andTINUVIN 765. The outer cover can also be formulated from a compositionincluding a prepolymer formed of H₁₂MDI and polyoxyalkylene, having amolecular weight of about 2000, cured with4,4′-bis-(sec-butylamino)-dicyclohexylmethane (Clearlink 1000). The golfball's outer cover layer is prepared according to the golf ballformation methods described in U.S. Pat. Nos. 5,733,428 and 5,888,437.

[0372] The inner cover or intermediate layer is comprised of athermoplastic composition such a blend of ionomers. Preferably, twoblends with different pigments are co-injected as set forth in U.S. Pat.No. 5,783,293 and co-pending U.S. application Ser. No. 10/055,232.Preferably, the inner cover can be comprised of an ionomer blend such asSURLYN 7940 and 8945, where the first portion contains between 1 and 10%by weight of or a first color such as Solvent Yellow 44 and a secondportion to be co-injected contains between 1 and 10% or a second colorsuch as white or blue. A favorable example can be made with a firstportion containing about 5% Solvent Yellow 44 and a second portioncontaining about 5% white concentrate, wherein the ball has about 10 to90% of its inner surface made of the first color and 90-10% of thesecond color. Still further, a small percentage of pigment or opticalbrightner can be added to the outer cover to provider further colorenhancement. Preferably, less than 0.05% pigment or optical brightner isadded to the outer cover. For really exceptional colors, the first andsecond portions of the inner cover can include pearlescent pigments suchas those from Mearl.

[0373] The cover of the embodiment was about 0.035 inches thick and theinner cover of intermediate layer was about 0.03 inches thick. Thesewere formed on a 1.55″ core as set forth above.

[0374] The invention described and claimed herein is not to be limitedin scope by the specific embodiments herein disclosed, since theseembodiments are intended as illustrations of several aspects of theinvention. Any equivalent embodiments are intended to be within thescope of this invention. Indeed, various modifications of the inventionin addition to those shown and described herein will become apparent tothose skilled in the art from the foregoing description. Suchmodifications are also intended to fall within the scope of the appendedclaims.

What is claimed is:
 1. A golf ball comprising a core, a cover and atleast on intermediate layer; wherein the intermediate layer is comprisedof pigment which contributes to the color of the ball; and wherein thecover is at least partially transparent and is comprised of an opticalenhancer.
 2. The golf ball of claim 1, wherein the optical enhancer is aflorescent dye.
 3. The golf ball of claim 1, wherein the opticalenhancer is an optically active chemical additive.
 4. The golf ball ofclaim 1, wherein the optical enhancer is optical brightner.
 5. The golfball of claim 1, wherein the cover is between about 0.01 and 0.05 inchthick.
 6. The golf ball of claim 5, wherein the intermediate layer iscomprised of a thermoplastic elastomer.
 7. The golf ball of claim 5,wherein the cover is comprised of an isocynate.
 8. The golf ball ofclaim 5, wherein the cover is substantially optically clear.
 9. The golfball of claim 1, wherein the intermediate layer is further comprised ofan optical brightener.
 10. The golf ball of claim 4, wherein the opticalbrightener comprises stilbene derivatives;4,4′bis-(2-benzoxazolyl)stilbene; styryl derivatives of benzene andbiphenyl; bis-(benzazol-2-yl) dirivatives; thiophene benzoxazole;coumarins; 7-(2h-naphthol (1,2-d)-triazol-2-yl)-3-phenyl-coumarin;carbostyrils; naphthalimides; derivatives ofdibenzothiophene-5,5-dioxide; pyrene derivatives; pyridotriazoles;derivatives of 4,4′-diamino stilbene-2,2′-disulfonic acid;4-methyl-7-diethylamino coumarin;2,5-bis(5-tert-butyl)-2-benzoxazolyl)thiophene; triazinolbenzenedisulfonic acid derivatives;2,2′-(1,2-ethenediylbis((3-sulfo-4,1-phenylene)imino(6-(diethylamino)-1,3,5-triazine-4,2-diyl)imino))bis-1,4-benzenedisulfonicacid hexasodium salt;2,5-thiophenediylbis(5-tert-butyl-1,3-benzooxazole; and mixturesthereof.
 11. The golf ball of claim 1, wherein the cover has an outersurface that includes a plurality of dimples covering at least 80% ofthe outer surface.
 12. A golf ball comprised of a ball precursor and asubstantially translucent cover having greater than 80% of an outersurface thereof covered by dimples.
 13. The golf ball of claim 12,wherein the ball has between about 300 and 360 dimples.
 14. The golfball of claim 12, wherein the golf ball has between about 360 and 400dimples.
 15. The golf ball of claim 12, wherein the golf ball hasbetween about 400-490 dimples.
 16. The golf ball of claim 12, whereinthe ball has a coefficient of restitution at 125 ft/sec of greater thanabout 0.81.
 17. The golf ball of claim 12, wherein the ball has acoefficient of restitution at 143 ft/sec of greater than about 0.78. 18.The golf ball of claim 12, wherein the ball precursor is comprised of acore and an intermediate layer.
 19. The golf ball of claim 18, whereinthe core has a diameter of greater than about 1.54 inches.
 20. The golfball of claim 19, wherein the core has a compression of between about 40and
 80. 21. The golf ball of claim 18, wherein the core has acompression of less than about
 40. 22. The golf ball of claim 18,wherein the core has a compression of between about 90 to
 120. 23. Thegolf ball of claim 19, wherein the cover is between about 0.01 and 0.05inch thick.
 24. The golf ball of claim 23, wherein the intermediatelayer has a thickness of about 0.02 to 0.04 inches.
 25. A golf ballcomprised of a ball precursor and a substantially translucent covercomprising an optical brightener comprised of stilbene derivatives;4,4′bis-(2-benzoxazolyl)stilbene; styryl derivatives of benzene andbiphenyl; bis-(benzazol-2-yl) dirivatives; thiophene benzoxazole;coumarins; 7-(2h-naphthol (1,2-d)-triazol-2-yl)-3-phenyl-coumarin;carbostyrils; naphthalimides; derivatives ofdibenzothiophene-5,5-dioxide; pyrene derivatives; pyridotriazoles;derivatives of 4,4′-diamino stilbene-2,2′-disulfonic acid;4-methyl-7-diethylamino coumarin;2,5-bis(5-tert-butyl)-2-benzoxazolyl)thiophene; triazinolbenzenedisulfonic acid derivatives;2,2′-(1,2-ethenediylbis((3-sulfo-4,1-phenylene)imino(6-(diethylamino)-1,3,5-triazine-4,2-diyl)imino))bis-1,4-benzenedisulfonicacid hexasodium salt;2,5-thiophenediylbis(5-tert-butyl-1,3-benzooxazole; and mixturesthereof, the cover having greater than 80% of an outer surface thereofcovered by dimples.
 26. The golf ball of claim 25, wherein the ball hasbetween about 300 and 360 dimples.
 27. The golf ball of claim 25,wherein the golf ball has between about 360 and 400 dimples.
 28. Thegolf ball of claim 25, wherein the golf ball has between about 400 and490 dimples.
 29. The golf ball of claim 25, wherein the dimples aresubstantially round.
 30. The golf ball of claim 25, wherein the ball hasa coefficient of restitution at 125 ft/sec of between about 0.81 and0.85.
 31. The golf ball of claim 25, wherein the ball has a coefficientof restitution at 143 ft/sec of between about 0.78 and 0.84.
 32. Thegolf ball of claim 25, wherein the ball precursor is comprised of a coreand an intermediate layer.
 33. The golf ball of claim 32, wherein thecore has a diameter of greater than about 1.54 inches.
 34. The golf ballof claim 32, wherein the core has a compression of between 40 and 80.35. The golf ball of claim 32, wherein the core has a compression ofless than about
 40. 36. The golf ball of claim 32, wherein the core hasa compression of about 90 to
 120. 37. The golf ball of claim 31, whereinthe cover is between about 0.01 and 0.05 inches thick.